Compare AI tools

	Lex A	NotebookLM S	Perplexity S	Devin A
Tagline	Google Docs with an AI collaborator baked in.	Google's research notebook. Turns your docs into a podcast.	AI search done right. Cited answers, not chat theater.	Cognition Labs' autonomous coding engineer.
Category	Writing	Research	Research	Agents
Pricing	Free + $12/mo	Free	Free + $20/mo Pro	$500/mo
Best for	Essays, long-form drafts, thinking on the page.	Students, researchers, anyone with a stack of PDFs or a topic to learn.	Replacing Google for any question where you want a cited answer in seconds.	Engineering teams offloading tickets. Ops/platform work.
Strengths	Clean writing UX — distraction-free +++ prompt triggers AI help Collaboration + AI feedback together	Upload anything, ask questions, get cited answers Audio Overview turns docs into a 10-min podcast Great for studying	Sources every claim Fast, current answers Pro Search runs multi-step research Spaces for persistent context	Works like an engineer — takes Slack tasks, opens PRs Handles multi-hour engineering work Reports back with what it did
Weaknesses	Less feature-rich than Google Docs AI ceiling below dedicated tools	Google-only Can be slow on large corpora	Not a general chatbot Answers can be shallow on complex topics	Expensive Best for well-scoped tasks Not for solo hobbyists
Kai's verdict	A-tier. Beautiful UX. The writing app I'd pick if I only wrote long-form.	S-tier for study. The Audio Overview is a killer feature. Try it with three of your favorite PDFs.	S-tier for search. I use it before Google now. If you're still Googling everything, try this for a week.	A-tier for the right use case. Not for solo devs. If you manage engineers, try one license.
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