Neutral mentions of SiteGround

If your priorities are multiple CMS platforms + daily backups + true reseller functionality, I’d focus on hosts that give you WHM/cPanel, Softaculous, isolated client accounts, white-labeling, and off-site backups.

My shortlist

KnownHost is particularly interesting for your requirements: its reseller hosting uses cPanel, CloudLinux and LiteSpeed, supports white-label branding, and includes JetBackup with daily backups and 2-day/1-week retention by default. KnownHost - Managed Hosting Specialists

InMotion Hosting is worth considering if you want the reseller-business side handled more completely, particularly billing automation. Current 2026 comparisons report cPanel/WHM and WHMCS as part of its reseller offering. iTechGuides CloudsPress

For CMS flexibility, Namecheap explicitly supports WordPress, Joomla, Magento and other applications through Softaculous, alongside WHM/cPanel reseller management. Namecheap

One caveat: SiteGround has excellent daily backups and white-label functionality, but its reseller model is more oriented toward managing multiple websites than the traditional WHM/cPanel model where you create independent hosting packages for customers. SiteGround

What I'd choose

For a web-design/development agency hosting client sites, I'd start by comparing KnownHost vs. InMotion. If you're building a more traditional hosting-reseller business where customers will have their own cPanel accounts and you want to sell packages under your brand, that's the workflow I'd prioritize.

If you tell me roughly how many client websites you expect (10, 50, 100+) and your monthly budget, I can narrow it down to the most suitable 2–3 plans and compare storage, CPU/RAM, backup retention, WHMCS, renewal pricing, and CMS support.