Grok Speech (STT + TTS APIs) vs Perplexity Comet

Perplexity Comet edges out Grok Speech (STT + TTS APIs) by 0.3 points (8.4 vs 8.1) -- a A-tier vs A-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 Comet's strengths, so if those categories are your priority, the lead translates.

On pricing, Perplexity Comet starts free while Grok Speech (STT + TTS APIs) requires a paid plan from day one ($0.10+). If you're testing the waters or running an occasional workload, that gap matters more than the score differential. Grok Speech (STT + TTS APIs) starts at $0.10; Perplexity Comet starts at $0. Compare what each entry tier actually unlocks before you compare list prices -- the limits matter more than the headline number.

By use case: pick Grok Speech (STT + TTS APIs) when developers building voice agents, real-time transcription tools, accessibility features, or high-volume tts workloads where the cost per hour of audio actually matters at scale. Pick Perplexity Comet when users who already use perplexity for search and want an agent browser that can complete multi-step tasks (booking, research, shopping, document summarization) across tabs. 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 Comet's lane, the tier-list ranking and the use-case fit point the same direction; if you're in Grok Speech (STT + TTS APIs)'s lane, the score gap matters less than the fit.

Bottom line: Perplexity Comet is the safer default for most readers, but Grok Speech (STT + TTS APIs) is competitive enough that the tie-breaker is your specific workload, not the spec sheet.