Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
BuzzSumo
Exceptional breadth and historical depth for content/media research.
The Content Research page claims a 5-billion-article index, competitive benchmarking and five years of data (https://buzzsumo.com/content-research/).
Pitchbox
Strong prospect and backlink research workflow, with SERP scraping, keyword/category search, competitor backlinks, SEO integrations, filters, and AI inspection.
The prospecting page documents SERP scraping, competitor backlink data, Ahrefs/Semrush imports, AI link-farm detection, and contact waterfalls: https://pitchbox.com/product/link-building-prospecting/