Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
Semrush
Deep keyword, competitor, backlink, and domain research workflows are explicitly documented.
SEO Toolkit lists competitor research, Keyword Gap, Keyword Overview, Keyword Magic Tool, backlinks, and related reports: https://www.semrush.com/kb/806-seo-toolkit
Siteimprove SEO
Strong enterprise SEO research coverage across competitors, SERPs, keywords, content gaps, and paid/organic data.
The SEO analytics page promises complete competitor strategies, deep SERP analysis, keyword monitoring, and paid/organic data: https://www.siteimprove.com/platform/seo/seo-analytics-tool/