What each platform is built for
Semrush positions itself as a unified marketing platform — SEO, paid search, content marketing, social media, and competitive analysis all in one subscription. The depth of the keyword and competitive databases is its core differentiator, with Canadian SERP data that is generally more granular than Moz's.
Moz Pro is a focused SEO suite — keyword research, rank tracking, site auditing, and link analysis. Moz pioneered the Domain Authority metric, which despite Google's repeated statements that it is not a Google ranking factor, remains a useful industry-recognised proxy for site authority comparisons.