I bought these headphones despite reading a lot of negative reviews. You have to take into consideration that for the price people buying these just want some decent headphones that give decent sound. If you're a proper audiophile then you're not going to be spending under 20quid!!
The sound is great, listened to all types of music from classical to drum and bass and it handles it well. I use these with my iPhone 3GS and the microhphone works great and people can hear me really clearly. The microphone has one button which has many features. It can be pressed once to answer an incoming call or hang up after the call is done. When the phone is idol one press starts the mp3 player and another then pauses it. If you double press then it skips to the next track, if you triple press then it goes back to the previous track. If you hold down the button then the voice activation starts.
The headphones feel very well made and they also come with a protective pouch, which is good because i was always shoving my old headphones in my bag and they got ruined.
If you want a good sound producing earphones with a mic for your iPhone then I would recommend getting these while they're cheap!