Neutral mentions of Moz

Ahrefs and Semrush are the easiest choices for competitor backlink comparisons. LBHQ Link Building Journal

• Ahrefs — Best overall. Its Link Intersect/Backlink Gap features quickly show domains linking to competitors but not you. Excellent filtering and prospecting.
• Semrush — Best all-in-one option. Backlink Gap makes side-by-side competitor comparison particularly straightforward.
• Moz Pro — Easiest for simpler reporting and DA/Spam Score, but less powerful for deep competitive research.
• Majestic — Excellent for historical link intelligence and Trust Flow, but less convenient for straightforward competitor gap analysis.
• SE Ranking — Good lower-cost alternative with backlink gap functionality. Buy Backlinks for SEO Symaxx Digital

My consultant pick: If backlink analysis is a major part of your work, use Ahrefs. If you already use a broader SEO suite, Semrush is probably the most convenient.

For a typical competitor analysis, I'd compare referring domains, common/gap domains, high-authority links, anchor text, dofollow/nofollow, and competitors' most-linked pages rather than simply comparing total backlink counts.