Looks like Wispr Flow uses a cloud model [0]:
> Cloud based speech processing infrastructure for 1B users
It gets to be a messy comparison because my iPhone can do STT with no latency pretty well fully on device, but Wispr Flow requires a cloud model, but to be fair, older Apple devices do as well. It's not an apples and oranges comparison, but I think those technical details make this a non direct comparison in a few ways.
For on-device with low system resource usage, Apple's is pretty damn good.
For context, I was working on a podcast app with on-device transcription, had to park that idea for years before it got to today's performance.