I bought a pair of mm400's recently - the bluetooth but not noise cancelling pair. £100 for active noise cancellation seemed way too extreme, particularly as I've not been overly impressed by NC in the past.
The mm400's do well on the bluetooth aspect though - the charge holds a good 5 hours of play, if not a great deal longer when in standby. They pair well with my laptop and phone, and range is good - i can wander from my laptop into the adjacent room, maybe 15m before they quickly lose reception - even they they stutter & eventually cut out, but haven't yet dropped connection. I haven't had a chance to try out the call quality on them yet - i didn't really intend to use them as a headset (wasn't even aware they had a microphone in them until after i'd bought them).
The sound quality over bluetooth is impressive too - I honestly don't notice the difference between wired and wireless. That said, I'm not blown away by either. The bass can be punchy, but there's an absence of true bass & sense of immersion. Generally midtones are reasonably lively, but not very clear at all, and the sound stage is pretty weak. It all just sounds very much on top of itself, and when there's a lot going on things sound muddled. For an outdoor, portable pair they're pretty good, and the passive noise isolation's not bad, but indoors they are a little disappointing.
P.S:: First review, hope it's helpful to someone. I should note the other pair I own are a pair of Sony MDRXD200's, which are a massive pair of over-ear open-backed 'phones, so perhaps I'm expecting too much from a small, portable, closed-back, on-ear pair. I'd like to hear what others think of them, so please post up if anyone else has these.
Edited by marc1uk - 8/10/10 at 7:19pm