For me and my friends the audio quality is fine, but the latency just kills it. There's like 150-200ms of delay (just guessing based on how it feels, haven't timed it properly). It's as bad as Skype in our testing.

It's probably fine if that's what you got used to, but going from low latency to higher latency is so jarring that I can't see us ever moving from mumble as long as it's still supported.