i got the mw600 last week and i'm really enjoying it.
connectivity between the desire and this device is excellent. i haven't had any kind of skipping even if i'm running outside.
the sound quality is good and if you don't like the sound quality, just swap headphones. swappable headphones are great because if your headphones crap out, you can replace them for a low cost.
the clip seems sturdy enough. but remember i only got it last week...
the battery life is great but i haven't fully discharge it yet (i don't plan to; that's not good for the Li ion battery)
i haven't had enough calls with it to say how good the microphone is...