Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
KWHero
Strong research workflow with keyword ideas, SERP data, clustering, and topical maps.
The homepage says users can discover opportunities with keyword ideas, SERP data, and AI-powered Topic Clusters, and can analyze search volume, difficulty, and SERPs: https://kwhero.com/
Scalenut
Deep SERP, competitor, topic, prompt, and page-level research is documented, though the site does not document every possible data source.
The Features FAQ says SERP statistics come from the top 30 ranking articles and Cruise Mode breaks down the top 10/20/30 competitor outlines: https://www.scalenut.com/features