Compare AI tools

	Perplexity S	NotebookLM S	Stable Audio A	ChatGPT Operator B
Tagline	AI search done right. Cited answers, not chat theater.	Google's research notebook. Turns your docs into a podcast.	Stability AI's open audio model. Loops + SFX + background.	OpenAI's browser agent. Clicks and types on websites for you.
Category	Research	Research	Audio	Agents
Pricing	Free + $20/mo Pro	Free	Free + $12/mo Pro + enterprise	Included with ChatGPT Pro $200/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.	Game developers, podcasters needing SFX, video creators needing background music.	Power users willing to pay $200/mo for a browser bot.
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	Open-weight model available Great for loops + game audio + SFX Commercial-use clarity	Actually uses websites — fills forms, clicks, checks out Built into ChatGPT Good for repetitive web tasks
Weaknesses	Not a general chatbot Answers can be shallow on complex topics	Google-only Can be slow on large corpora	Not for full songs with vocals Shorter generation limits	Slow vs doing it yourself Breaks on complex auth flows $200/mo gate
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 for its niche. Different use case than Suno — SFX and loops, not songs.	B-tier. Still early. Manus is more flexible for less money.
Link	Open →	Open →	Open →	Open →