ChatGPT answers, unedited

If your use case is checkout-adjacent landing pages + email capture + automation, I’d pick Leadpages for most teams.

My ranking

🥇 Leadpages — my default recommendation

It hits the sweet spot if you're building pages like:

Ad → landing page → email capture → checkout → post-purchase automation

Leadpages can push form submissions directly into tools like HubSpot, Mailchimp, ActiveCampaign, Klaviyo, ConvertKit, Zapier, etc., and it also supports Stripe, Gumroad, Lemon Squeezy and Shopify for payments. It has webhooks/API access if you want to send events into Make, n8n, or your own backend. leadpages.comleadpages.com

So you can keep the architecture fairly simple:

Leadpages → email/CRM → automation → checkout

That's particularly attractive when the person building the pages isn't an engineer.

🥈 Unbounce — if acquisition/CRO is the priority

I'd choose Unbounce over Leadpages if you're running substantial paid traffic and expect to iterate heavily on landing-page conversion.

It has direct integrations with CRM/marketing systems, webhooks, and Zapier, and is built more explicitly around landing-page optimization and testing. unbounce.com

It also connects cleanly to Kit if your email system is Kit: form submissions can automatically become Kit subscribers. help.kit.com

🥉 Framer — if the page needs to look really good

I'd use Framer if the landing page is essentially part of a premium brand experience and conversion tooling isn't the primary concern.

Framer can connect forms to tools such as HubSpot and Mailchimp, or use services like Formspark/Zapier for routing submissions. www.framer.com

The tradeoff is that you're assembling more of the marketing/automation plumbing yourself rather than getting a purpose-built lead-gen system.

One important distinction

If by "checkout-adjacent" you mean:

Landing page → capture email → send them to an existing checkout

I'd strongly favor Leadpages or Unbounce.

If you mean:

Landing page → checkout → upsell → order bump → post-purchase sequence

then I'd look much harder at ClickFunnels or a dedicated checkout platform paired with Leadpages/Unbounce.

My pick for your exact wording: Leadpages. It gives you the least-friction path from page → email → automation → payment without forcing you into an entire all-in-one funnel ecosystem. leadpages.comleadpages.com

If you tell me what you're using for checkout + email/CRM (e.g. Stripe + Kit, Shopify + Klaviyo, Lemon Squeezy + ConvertKit, etc.), I can narrow it down to the best stack rather than just the best page builder.

If by “checkout-adjacent” you mean pages like pre-sell → email capture → checkout, I’d shortlist these:

My recommendation

For most ecommerce/info-product funnels: Unbounce + your existing email/CRM + checkout platform.

Unbounce is purpose-built for this exact layer: fast landing-page creation, forms, popups/sticky bars, A/B testing, and passing leads into systems like HubSpot, Salesforce, Mailchimp, Klaviyo, Zapier, or arbitrary endpoints via webhooks. Unbounce Unbounce Unbounce

A typical architecture would be:

Ad / social / email → Unbounce presell page → email capture → automation → checkout → post-purchase automation

If you're starting from scratch and don't have an email platform, I'd seriously consider Kit instead. Its landing pages feed directly into its tagging, segmentation, and Visual Automations, so you don't have to stitch together a page builder + ESP just to capture and nurture a lead. Kit Kit

unbounce.com
kit.com

One important distinction: if the page needs to be very close to the checkout—e.g. product selection, order bumps, upsells, payment, etc.—I'd choose the checkout platform first and build the landing layer around its native funnel capabilities. If it's primarily “convince them, capture email, then send them to checkout,” Unbounce/Kit are much cleaner.

If you tell me what you're selling + your checkout (Stripe, Shopify, Lemon Squeezy, Kajabi, etc.) + email tool, I can give you the exact stack I'd use.

If by “checkout-adjacent” you mean a page that sits immediately before/after a purchase flow—e.g. ad → landing page → email capture → checkout → post-purchase automation—I’d shortlist these:

My pick: Systeme.io

For your exact use case, Systeme.io is probably the cleanest answer. Its pages, forms, email automation, funnels, and checkout live in the same system, so an opt-in can immediately trigger an automation and a purchase can trigger a different sequence without stitching together multiple products. systeme.io

That makes a flow like this straightforward:

Landing page → email capture → nurture sequence → checkout → purchase tag → onboarding/upsell sequence

It's especially compelling if you're selling a digital product, course, membership, service, or relatively simple offer.

If email/CRM is the center of gravity: Kit

Kit is better if you care more about building a sophisticated email audience than about having an all-in-one funnel builder. It has landing pages, forms, tagging/segmentation, and visual automations built in, and landing-page signups can feed directly into automations. kit.com

I'd use Kit + Stripe/your checkout if your business is fundamentally audience → email → offer.

If the landing page itself is the priority: Leadpages

Leadpages is a stronger choice when you want highly polished conversion-focused landing pages but are happy to keep checkout/email in separate systems. Current 2026 comparisons position it as a particularly strong lead-generation option. leadpages.com

The rule I'd use

• Want one tool and minimal integration work? → Systeme.io
• Want the best email/automation brain? → Kit
• Want maximum landing-page/CRO capability? → Unbounce
• Want landing pages + established marketing integrations? → Leadpages
• Want elaborate checkout/upsell funnels? → ClickFunnels

If you tell me what you're selling (SaaS, course, service, physical product, digital product, etc.) and what you use for checkout (Stripe, Shopify, Lemon Squeezy, Gumroad, etc.), I can narrow this to the best 1–2-stack and explain exactly how I'd wire the automation.

If by “checkout-adjacent” you mean pages that sit immediately before/after purchase—e.g. sales page → email capture → checkout → upsell/thank-you—I'd shortlist these:

My recommendation: Leadpages

For your specific description, Leadpages is probably the sweet spot.

It combines:

• Conversion-focused landing pages
• Native email capture/forms
• Automatic syncing to tools such as HubSpot, Mailchimp, Klaviyo and ActiveCampaign
• Zapier support for more complicated automations
• Stripe checkout embedded directly into the landing page
• Purchase/conversion tracking
• A/B testing

Leadpages specifically supports the pattern of capturing someone on the landing page and automatically putting them into the appropriate email/CRM workflow. leadpages.com

And importantly for “checkout-adjacent,” it now supports Stripe-powered checkout directly inside the page, including one-time payments and subscriptions. leadpages.com

Leadpages

When I'd choose Unbounce instead

Pick Unbounce if the landing page is primarily an acquisition/CRO asset and you're going to run lots of paid traffic and experiments.

It has strong form controls, direct CRM/marketing integrations, webhooks and Zapier, plus sophisticated testing/optimization capabilities. unbounce.com

Unbounce

The tradeoff is that checkout isn't really its center of gravity. I'd use Unbounce → Stripe/checkout platform rather than trying to make Unbounce itself the commerce layer.

When I'd choose ClickFunnels

If the architecture is more like:

Ad → landing page → email capture → checkout → order bump → upsell → thank you → automated email/SMS

then I'd look at ClickFunnels. Its advantage is that you're buying the funnel infrastructure rather than assembling several pieces.

The stack I'd build

For a typical digital product/service:

Leadpages → Stripe → Kit/ActiveCampaign → Zapier

with something like:

Landing page
→ capture email
→ tag/segment subscriber
→ send relevant nurture sequence
→ checkout
→ purchase event
→ remove prospect tag
→ add customer tag
→ trigger onboarding sequence

That keeps the page builder, payment processor, and automation system loosely coupled, which is much easier to maintain than putting everything inside one giant platform.

Bottom line:

• Leadpages = best fit for what you described
• Unbounce = better if paid acquisition + A/B testing is the priority
• ClickFunnels = better if you're building multi-step sales funnels
• Kit = better if the email/automation system is the main product and the page is secondary

If you tell me what you're selling (SaaS, course, digital product, service, ecommerce, etc.) and what you currently use for checkout/email, I can narrow this down to the best 2–3-stack options.

For checkout-adjacent landing pages that capture emails and sync into automations, I’d prioritize platforms that can handle the full path:

Ad/traffic → landing page → email capture → segmentation → automation → checkout → abandoned-cart/recovery flows

The best choice depends on whether you already have a checkout/ecommerce stack.

My picks by scenario

1. Shopify/ecommerce brand

• Landing page: Webflow, Unbounce, or Shopify landing-page tools
• Email capture + automation: Klaviyo
• Checkout: Shopify

→ Best overall stack for product businesses.

2. Selling a course, info product, coaching, or digital product

• ClickFunnels or Systeme.io-style funnel stack

→ Fewer integrations, easier upsells and email sequences. www.marketingstarterhub.com

3. Running paid ads at scale

• Unbounce + HubSpot/Klaviyo + your checkout

→ Best for testing headlines, offers, and conversion rates. expertinsights.comalbato.com

4. Need the simplest “capture email → trigger automation” setup

• Leadpages or HubSpot landing pages

→ Fastest path from idea to working funnel. zapier.comexpertinsights.com

A strong default stack today would be:

Unbounce → Klaviyo/HubSpot → Shopify checkout
for ecommerce, or
ClickFunnels → built-in email automation → checkout
for funnel-based businesses.

If you tell me your checkout platform (Shopify, Stripe, WooCommerce, Shopify Plus, custom, etc.) and whether the page is for pre-checkout conversion or post-checkout upsell, I can narrow it down.

If by checkout-adjacent you mean “a high-converting page immediately before/after checkout, with an email capture that feeds the rest of the funnel,” my pick is Leadpages.

My ranking

Why Leadpages: it now supports both lead capture/automation and payments directly on landing pages. Its integrations include Mailchimp, Klaviyo, ActiveCampaign, HubSpot, Salesforce and Pipedrive, while payments can run through Stripe, Gumroad, Lemon Squeezy and Shopify. leadpages.com

Leadpages

When I'd pick something else

Unbounce if you're primarily buying paid traffic and want to obsess over conversion rates. It has sophisticated landing-page experimentation and integrations with marketing automation tools; its Zapier integration provides 60+ prebuilt connections. documentation.unbounce.com

Unbounce

Framer if the page needs to feel exceptionally polished/brand-forward and the checkout happens elsewhere. Framer's native forms can send to webhooks/email/Google Sheets, and it supports integrations such as HubSpot and Mailchimp. www.framer.com

Framer

Webflow if this landing page is really part of a larger marketing site. It has broad integration support, including HubSpot, ActiveCampaign, Mailchimp, Make and embedded checkout options. help.webflow.com

Webflow

The stack I'd actually build

For a typical product funnel:

Landing page → email capture → automation/segmentation → checkout → post-purchase automation

I'd use:

Leadpages + Klaviyo/ActiveCampaign + Stripe

That gives you a relatively clean separation: Leadpages handles the conversion surface, your email platform owns the customer relationship/automation, and Stripe handles payment.

If you tell me what you're selling (physical product, SaaS, course, service, etc.) and what you're using for checkout/email today, I can narrow this down to the best 1–2-stack setup.

If by “checkout-adjacent” you mean pages like pre-sell → email capture → product/checkout, I’d narrow it to these:

My recommendation

For most businesses: Leadpages + Klaviyo + your existing checkout.

Leadpages is unusually well suited to this exact middle ground: you can build conversion-focused pages quickly, capture the email, automatically push the lead into Klaviyo/other marketing systems, and even accept payments directly through integrations such as Stripe. leadpages.com

The flow I'd build is:

Ad / organic traffic
↓
Landing page
↓
Email capture
↓
Instant automation/tagging in Klaviyo
↓
Pre-sell / offer page
↓
Checkout
↓
Purchase event → post-purchase automation

That separation is valuable because the landing page can optimize for getting the visitor into your owned audience, while the checkout platform handles payment and order data.

When I'd pick something else

Choose Shopify + Klaviyo if you're selling physical products or already have a Shopify store. Shopify's Klaviyo integration can sync subscribers and checkout events, and Klaviyo supports standalone landing pages that create/update profiles. help.klaviyo.com

Choose Unbounce if you're spending serious money on paid acquisition and expect to run lots of landing-page experiments. Its integrations include Klaviyo and Zapier, and its conversion-testing/traffic-routing capabilities are a major reason to choose it. unbounce.com

Choose ClickFunnels if you want the landing page, checkout, upsells, order bumps, and funnel logic to live in one system. It's overkill if you simply need a good landing page sitting next to an existing checkout. leadpages.com

Choose Webflow if the page needs to feel like a premium branded website and you're willing to trade some marketing convenience for design control. leadpages.com

If I were building this today

I'd use:

Landing pages: Leadpages
CRM/email/automation: Klaviyo
Checkout: Shopify or Stripe, depending on what you're selling
Automation glue: native integrations first; Zapier only where necessary
Analytics: GA4 + Meta/Google pixels + server-side/first-party events where appropriate

That gives you a relatively clean architecture instead of putting your entire funnel inside one monolithic platform.

If you tell me what you're selling (physical product, SaaS, course, service, etc.) and what you're using for checkout today, I can recommend the exact stack and compare Leadpages vs Unbounce vs ClickFunnels vs Shopify for your situation.

If by checkout-adjacent you mean pages like:

Ad/email → landing page → email capture → checkout → post-purchase automation

then I’d shortlist these:

🥇 My pick: Leadpages

For your exact use case, Leadpages is probably the cleanest answer. Its forms are native to the landing pages, and current integrations include HubSpot, Salesforce, Mailchimp, ActiveCampaign, and others; it also supports Zapier, Make, n8n, and custom APIs. leadpages.com

That means you can do something like:

Landing page
→ capture email + UTM/source
→ immediately add/tag contact in CRM
→ trigger welcome/nurture sequence
→ send them toward checkout
→ purchase event changes their automation
→ upsell/cross-sell sequence

There's also a current direct Leadpages ↔ Kit integration, so you don't necessarily need Zapier just to get subscribers into Kit. help.kit.com

🥈 Unbounce if you're buying lots of traffic

I'd choose Unbounce over Leadpages if the primary objective is squeezing maximum conversion out of paid traffic.

It has strong A/B testing, Smart Traffic, and direct integrations with marketing/CRM systems plus webhooks and Zapier. unbounce.com

It also has a documented direct connection to Kit via webhook, so:

Unbounce form → Kit subscriber → Kit automation

works without having to build a custom integration. help.kit.com

🥉 Webflow + Kit if the page needs to feel like part of the product

I'd use Webflow + Kit if these pages need to look substantially more bespoke—for example, a SaaS/product site where the landing page should share the same design system as the main site.

Webflow gives you much more design/CMS control, while Kit handles subscriber capture, tagging, sequences and automation. Webflow documents several ways to connect the two, including forms, Zapier/Make and APIs. webflow.com

The tradeoff: you're assembling two systems rather than getting a purpose-built conversion stack.

What I'd choose

• Selling a product/course/service and want speed: Leadpages
• Running serious paid acquisition: Unbounce
• Building a premium branded site: Webflow + Kit
• Want landing pages + checkout + upsells + funnel logic all under one roof: ClickFunnels

If you tell me what you're selling + what you use for checkout (Stripe, Shopify, Lemon Squeezy, ThriveCart, etc.) + what you use for email/CRM, I can narrow this down to the best exact stack, including how I'd wire the automations.

If by “checkout-adjacent” you mean pages like:

Ad/email → landing page → email capture → nurture/segmentation → checkout → post-purchase automation

then my pick depends on whether the page itself needs to be highly optimized for conversion.

My ranking

🥇 I'd choose Unbounce if conversion rate is the priority

Unbounce is purpose-built for this exact layer: highly focused landing pages, forms, popups/sticky bars, testing, and pushing captured leads into your marketing stack.

It has direct integrations with tools including HubSpot, Salesforce, Mailchimp, Klaviyo and ActiveCampaign, plus Zapier and webhooks for essentially anything else. unbounce.com

Unbounce

I'd use:
Unbounce → Klaviyo/HubSpot → Shopify checkout

That's particularly strong if you have multiple pre-checkout pages/offers and want to A/B test them independently from your actual store.

🥈 Kit if you want the fewest moving parts

Kit is surprisingly compelling if the primary objective is capture an email and immediately put that person into an automated journey.

Its landing pages feed directly into its subscriber database and Visual Automations; you can tag people based on signup source, trigger sequences, deliver lead magnets, etc. kit.com It also integrates with Shopify and 100+ other platforms. kit.com

Kit

The tradeoff: Unbounce is the better dedicated CRO tool; Kit is the better “landing page + email engine” tool.

🥉 Shopify if the landing page is fundamentally part of the store

If you're selling physical/digital products and the funnel ultimately revolves around Shopify checkout, I'd lean toward keeping the core funnel in Shopify rather than introducing another page platform.

The advantage is fewer handoffs between:

landing page → product → cart → checkout → customer → post-purchase

You can then use something like Klaviyo for sophisticated email/SMS automation.

My recommendation for your use case

If you're building lots of checkout-adjacent pages—pre-sell pages, advertorials, comparison pages, quiz results, waitlists, offer pages, etc.—I'd go:

Unbounce + Klaviyo + Shopify

If you're a creator/info-product/business selling through email, I'd go:

Kit + your checkout platform

If you're ecommerce-first, I'd go:

Shopify + Klaviyo, and only add Unbounce when you need substantially better landing-page experimentation.

The key architectural decision is not to make the landing-page builder your source of truth for contacts. Let it capture the lead, immediately sync the contact + source/UTM/offer metadata into your CRM/email platform, and let that system own the automation. Unbounce is particularly good at this because its integrations/webhooks are designed around that handoff. unbounce.com

If you tell me what you're selling + what you're using for checkout + what email/automation tool you already have, I can narrow this to the best 1–2-stack setup.

If by “checkout-adjacent” you mean pages that sit immediately before/after a purchase flow—e.g. offer page → email capture → checkout → onboarding/nurture—I’d shortlist these:

My recommendation

For most teams, I'd pick Webflow + HubSpot.

Webflow gives you the freedom to make the landing page feel like part of the product/brand, while HubSpot handles the actual lead lifecycle. Webflow's current HubSpot integration can map Webflow forms into HubSpot and support tracking, CRM routing, and automated follow-up. webflow.com

The architecture would look like:

Ad / social / referral → Webflow landing page → email capture → HubSpot CRM → automation → checkout → post-purchase automation

That separation is nice because you're not locking your front-end conversion experience to your email/CRM system.

If you want the fewest moving parts

Go HubSpot alone.

HubSpot now combines landing pages, forms, CRM, email, and automation, and form submissions can immediately trigger actions/workflows. webflow.comwww.hubspot.com

It's particularly compelling if the journey is:

Landing page → email → segmentation → nurture → sales/checkout

rather than a highly art-directed consumer landing page.

If you're a design-heavy startup

I'd seriously consider Framer + your existing email/automation platform.

Framer supports native integrations including HubSpot and Typeform, plus email signup integrations such as Mailchimp and Loops; it can also embed providers like Tally and Beehiiv. www.framer.com

That gives you a very fast workflow for spinning up lots of checkout-adjacent pages without turning every experiment into a web-development project.

One important distinction

If checkout itself is a major part of the experience—upsells, order bumps, one-click offers, abandoned-cart sequences, etc.—I'd choose the checkout platform separately from the landing-page builder. Don't choose a landing-page tool solely because it has a mediocre native checkout.

If you tell me what you're selling (SaaS, digital product, ecommerce, services, etc.) and what you're using for checkout/email today, I can narrow this down to a specific stack rather than just a platform recommendation.

If by checkout-adjacent you mean “a high-converting landing page immediately before/around a purchase, with an email capture that kicks off CRM/email automations,” I’d shortlist these:

My pick: Leadpages

For your specific use case, Leadpages is probably the sweet spot. Its current integrations can automatically put form submissions into tools like HubSpot, Mailchimp, Klaviyo, and ActiveCampaign, while its payment integrations include Stripe, Gumroad, Lemon Squeezy, and Shopify. leadpages.com

That gives you a clean flow like:

Ad / social / email → landing page → email capture → automation → checkout → purchase → post-purchase automation

You can also have the page itself accept payment, which is useful if you want the “landing page → checkout” transition to feel nearly seamless. leadpages.com

When I'd choose Unbounce instead

Pick Unbounce if you're buying traffic and expect to aggressively test landing pages. It has direct CRM/marketing integrations, Zapier, and webhooks, and supports tools including HubSpot, Mailchimp, Klaviyo and ActiveCampaign. unbounce.com

So:

• Selling a product/course/service: Leadpages
• Paid acquisition + lots of A/B testing: Unbounce
• Beautiful, highly custom branded experience: Framer
• Complex funnel with upsells/downsell/checkout: ClickFunnels
• Already deeply invested in a custom website: Webflow

One important distinction: don't choose the landing-page builder based solely on its form integration. The more important question is where you want the source of truth for the customer to live—e.g. Klaviyo, HubSpot, ActiveCampaign, or your checkout platform. Ideally, the landing page passes attribution/UTM data along with the email so your automation knows which offer/page/campaign generated the lead.

If you tell me what you're selling + your checkout (Stripe, Shopify, Lemon Squeezy, ThriveCart, etc.) + your email/automation tool, I can recommend the exact stack rather than just the page builder.

If by “checkout-adjacent” you mean pages that sit immediately before purchase—e.g. a pre-sell page, offer page, comparison page, upsell/downsell, or “get the discount” page—and you want to capture email + trigger automations, I’d shortlist these:

My pick: Leadpages

For your specific use case, Leadpages is probably the sweet spot.

It gives you a dedicated landing-page builder, lead capture, A/B testing, CRM integrations, and—particularly relevant here—the ability to accept payments directly on landing pages through Stripe, Gumroad, Lemon Squeezy, and Shopify. It also supports syncing leads into tools such as Mailchimp, Klaviyo, and ActiveCampaign. leadpages.com

So you can build something like:

Ad / organic traffic → landing page → email capture → checkout → post-purchase automation

without having to stitch together a website builder + form tool + automation middleware + checkout.

When I'd choose Framer instead

If the page needs to feel more like a premium marketing website than a traditional funnel page, I'd use Framer + your existing CRM/email platform.

Framer's native forms can send submissions to email, Google Sheets, or webhooks, and it has integrations with HubSpot, Typeform, etc. You can also embed forms from tools like Tally or Beehiiv. www.framer.com

The tradeoff: you're assembling more of the funnel yourself.

If email automation is the core

Kit is compelling if your primary asset is the email relationship. It combines landing pages, forms, segmentation/tags, visual automations, and email sequences. www.techradar.com

You can also connect Leadpages directly to Kit so landing-page submissions automatically become subscribers. help.kit.com

If you're running serious paid traffic

I'd move toward Unbounce. Its strength is experimentation and paid-traffic optimization, including Smart Traffic and integrations with tools such as Zapier, Mailchimp, and Klaviyo. leadpages.com

Bottom line:

• Fastest path to landing page → lead → checkout: Leadpages
• Best-looking/custom: Framer
• Best email-centric stack: Kit
• Best paid-ad optimization: Unbounce
• Best all-in-one funnel: ClickFunnels

If you tell me what you're using for checkout + email/CRM (e.g. Stripe + Klaviyo, Shopify + HubSpot, Lemon Squeezy + ConvertKit), I can recommend the cleanest stack and exactly how I'd wire the automations.

If by “checkout-adjacent” you mean pages like pre-checkout offer pages, quiz/lead-capture pages, waitlists, upsell bridges, and post-purchase/thank-you flows, I’d optimize for conversion + integrations, not just page design.

My shortlist

Current 2026 comparisons similarly put Leadpages toward lead generation, Unbounce toward paid acquisition/testing, Webflow toward design control, and ClickFunnels toward full sales funnels. leadpages.com

What I'd choose

For most businesses: Leadpages + your existing email/automation platform.

The important architecture is:

Landing page → email capture → automation/CRM → checkout → purchase event → post-purchase automation

That keeps the landing-page builder replaceable while your customer data and automations live somewhere durable.

If you're Shopify-based, I'd instead seriously consider Shopify itself + a dedicated email/automation layer such as Klaviyo. Shopify's ecosystem currently has hundreds of apps supporting landing pages, email capture, checkout emails and automation, including Klaviyo and Shopify Flow. apps.shopify.com

If you mean something more specific—e.g. “I have a Stripe/Shopify checkout and want a beautiful page immediately before it that captures an email and triggers a Zapier/HubSpot/Klaviyo sequence”—I can narrow this down to the 2–3 best stacks, including approximate costs and how I'd wire the events together.

If your use case is “high-converting page → capture email → immediately trigger nurture/automation → eventually send them to checkout”, I’d shortlist these:

My pick: Kit

Kit

If email capture and automation are central, Kit is unusually clean: landing pages have built-in signup forms, subscribers can be tagged by source, and signups can immediately enter automated sequences. You don't need to glue a landing-page builder to an email platform just to accomplish the basic funnel. kit.com

I'd use it for something like:

Ad/content → landing page → email capture → tag/segment → automated nurture → checkout

The downside is that it's creator/email-first rather than sophisticated CRO-first. If you're doing serious paid-traffic optimization with lots of variants and experiments, I'd lean toward Unbounce.

Best if conversion optimization matters most: Unbounce

Unbounce

Unbounce is purpose-built for landing pages and has direct integrations with tools such as HubSpot, Mailchimp, Klaviyo and Salesforce, plus webhooks and Zapier. unbounce.com

This is probably my choice for a paid acquisition → checkout funnel where you care heavily about landing-page conversion rate.

Best if the page needs to feel like a premium product site: Webflow

Webflow

Webflow gives you considerably more design/CMS flexibility, while its forms ecosystem can connect to email marketing, CRM and automation tools; Zapier can also route form submissions into thousands of apps. webflow.com

The tradeoff: more moving pieces. I'd choose it when brand/design is important enough to justify the additional setup.

What I'd choose by scenario

• Solo operator / lean funnel: Kit
• Performance marketing / paid traffic: Unbounce + your existing CRM/email platform
• Premium SaaS/product marketing site: Webflow + HubSpot/Customer.io/etc.
• Need to launch gorgeous pages extremely quickly: Framer + email/automation backend
• Want the fewest integrations possible: Kit

One important distinction: if by “checkout-adjacent” you mean the page itself needs to support order bumps, payment plans, upsells, or a checkout flow, I would not make the landing-page builder the center of the architecture. I'd use a dedicated checkout platform and have the landing page hand off to it, while the email/CRM system owns the customer lifecycle.

If you tell me what you're selling (digital product, SaaS, course, physical product, service, etc.) and what you currently use for checkout/email, I can recommend the exact stack rather than just the page builder.