First off - I just want to cover compatibility with the iPhone 3G as I searched for details before buying them but couldn't find any, so took a risk:
Play/pause works but FF and Rew DO NOT work. Suspect this is an iPhone issue - as the FF and Rew controls work fine when using them with my BlackBerry. I use my BH905 with my iPhone every day and really pleased with the performance, aside from the fact that I have to get my iPhone out of my pocket to skip tracks. Haven't tried with iPhone 3GS.
One note someone else mentioned - the noise canceling feature does seem to respond a bit strangely to sudden changes in air pressure. For example, when I'm in the back of a car listening with the noise canceling activated and we pass a lorry going the other way, you get a short whoosh and a knocking sound for a split second. I guess this is the headphones trying to cancel the 'noise' from the air pressure of the lorry passing by but it doesn't really work. Also sometimes there is a vibrato effect slightly evident.
I've only found this in a car - on the bus it's not there (larger volume so the air pressure change isn't so evident? I dunno..) and on the train or plane it's also fine. Switching off the noise cancellation removes this effect immediately.
I can't give them 5 stars because of this.
Battery life with the iPhone, listening to music with noise cancellation turned on for about 4 hours per day is approx 2-3 days... so about 10 hours. I know the website says 16 hours - i think that's too high from my experience, but 10 hours is acceptable to me.