We're using AssemblyAI too, and I agree that their transcription quality is good. But as soon as Whisper supports world-level timestamps, I think we'll seriously consider switching as the price difference is large ($0.36 per hour vs $0.9 per hour).
It’s based on a finetuned Whisper and you’d get unlimited transcriptions for $4.99/month
It has great quality transcription from video and audio (in English only sorry if that's not you!). Uses Whisper.cpp plus VAD to skip silent / non-speech sections which introduce errors normally. Give a try let me know what you think! :)