> if anything starts using the microphone, it switches modes and the audio quality goes way, way down.

Funny, I don't see this on windows, which will leave the headphones at high quality (except for when I'm speaking, at which point I don't care that much about audio) - but on Linux I have to set the audio profile for the headset to low quality in order to enable the microphone at all - so all audio out is crap as long as I'm on a call/have the microphone enabled (even muted).

Still waiting for this to improve - but looks like it'll require new hw (new Bluetooth receiver and sender).