Perplexity AI edges out NotebookLM by 0.7 points (8.5 vs 7.8) -- a A-tier vs B-tier split that's narrow but real. Not a blowout; both belong on a shortlist. The score gap shows up most clearly in the categories that matter for Perplexity AI's strengths, so if those categories are your priority, the lead translates.
Pricing-wise, both tools have a free tier (Perplexity AI starts $0, NotebookLM starts $0), so you can test either without committing. Compare what each free tier actually unlocks -- usage caps, model access, and feature gates differ a lot more than the headline price suggests, especially as both vendors have tightened limits in 2026.
By use case: pick Perplexity AI when researchers, students, professionals, and anyone who needs factual answers with sources. Pick NotebookLM when students researching papers, professionals who need to quickly digest long documents, and anyone who wants to turn a pile of pdfs into something they can query and listen to. The two tools aren't fighting for the same person -- they're aiming at adjacent jobs that occasionally overlap. If you're squarely in Perplexity AI's lane, the tier-list ranking and the use-case fit point the same direction; if you're in NotebookLM's lane, the score gap matters less than the fit.
Bottom line: Perplexity AI is the safer default for most readers, but NotebookLM is competitive enough that the tie-breaker is your specific workload, not the spec sheet.