Compare AI tools

	Perplexity S	NotebookLM S	Aider A	Devin A
Tagline	AI search done right. Cited answers, not chat theater.	Google's research notebook. Turns your docs into a podcast.	Terminal-based AI pair programmer. Git-aware, model-flexible.	Cognition Labs' autonomous coding engineer.
Category	Research	Research	Coding	Agents
Pricing	Free + $20/mo Pro	Free	Free (open source) + whatever API you use	$500/mo
Best for	Replacing Google for any question where you want a cited answer in seconds.	Students, researchers, anyone with a stack of PDFs or a topic to learn.	Developers who want open-source tooling with full control.	Engineering teams offloading tickets. Ops/platform work.
Strengths	Sources every claim Fast, current answers Pro Search runs multi-step research Spaces for persistent context	Upload anything, ask questions, get cited answers Audio Overview turns docs into a 10-min podcast Great for studying	Works in any terminal Auto-commits changes with meaningful messages Works with any model (Claude, GPT, local) Minimal learning curve	Works like an engineer — takes Slack tasks, opens PRs Handles multi-hour engineering work Reports back with what it did
Weaknesses	Not a general chatbot Answers can be shallow on complex topics	Google-only Can be slow on large corpora	Terminal-only Less agentic than Claude Code Setup on Windows is fiddly	Expensive Best for well-scoped tasks Not for solo hobbyists
Kai's verdict	S-tier for search. I use it before Google now. If you're still Googling everything, try this for a week.	S-tier for study. The Audio Overview is a killer feature. Try it with three of your favorite PDFs.	A-tier. The right answer if you want open-source + terminal-native + model-agnostic.	A-tier for the right use case. Not for solo devs. If you manage engineers, try one license.
Link	Open →	Open →	Open →	Open →