Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
Page Optimizer Pro
Competitor and page analysis provides solid on-page research without the breadth of a general SEO suite.
POP analyzes ranking competitors and more than 100 on-page signals: https://pageoptimizer.pro/
Textmetrics
Useful on-page SEO/content analysis, but no broad SEO research database is documented.
The Editor offers keyword ideas and analyzes keyword relevance for titles, headings and metadata, but the official feature description does not claim backlink, SERP, competitor or market research. https://textmetrics.com/seo-geo/