So, as promised, I now have some miles on this unit and thought I would share some further information.
I have worn this roughly every day since July. My normal week consists of an early Monday morning commute of around 155 miles followed by a 60 mile round trip every day from Tuesday to Thursday followed by the return 155 mile leg on a Friday (so roughly 500 miles a week). This is in all weathers and a combination of City riding (Tues-Thurs) and motorway / highway on Monday and Friday.
Battery life - still getting around 4-5 hours from a full charge and this includes either the radio or iphone music constantly on the whole time. The unit beeps periodically in your ears when the battery is getting low giving you approx another 20-30 mins of use before it fails.
The included headphones are "OK" for around town and, at a push on the motorway at 80-90mph with ear plugs but sound quality gets pretty crappy at that stage and very faint. The Sennheisers work great with this unit and replace both the included headphones along with my ear plugs - they do double-duty - sound quality is superb, volume is very high and outside noise is nicely attentuated to a similar level to wearing plugs - no more headaches. The bass response is also very good and they are comfortable to wear for long periods inside a helmet.
The mic is crystal clear for speech on the phone and the noise cancelling is excellent. The AGC (automaticlly gets louder up to a pre-set point the faster you go) is superb and is most noticeable when pulling into town from motorway speeds, reducing nicely so as to remain comfortable when trickling and no background noise.
The controls on the unit itself take a little bit of getting used to as there are only 2 main buttons which involves combinations of long presses, short presses, double and triple clicks - but it's straightfoward enough. I particularly like being able to store a phone number on the unit which it will dial automatically if you triple click the main button - very handy for calling the wife on the way home.
It will store 6 radio stations as pre-sets but you can retune very easily when on the move. With RDS engaged it will automatically re-tune itself to a stronger signal when travelling. The volume + and - buttons double up as tuners (up and down) when in radio mode if you hold them in for a few seconds.
It has two bluetooth pairing channels meaning you can pair two different devices at the same time - I have two phones paired but you could just as easily make one of these a Sat Nav or whatever else you're in to.
It is small, light and comfortable on the helmet - no noticeable increase in wind noise on the helmet (but then I always have the screen up when on the motorway).
In short - at the moment I would highly recommend this unit and I have not used half of its capabilities (haven't even tried the intercom mode) - if it crapped out tomorrow, I would buy another one immediately - it has transformed my weekly grind of a commute making it more informative, entertaining and making it seem to pass much quicker - I don't know how I managed without one for so long!!
Any questions, please ask!
Darren