In case you didn't read it, this is what Giz had to say about the mic:
The mic, or its location, probably, gave my voice a boomier sound than I got from the Vibes or the Etymotics, though I remained completely intelligible, and background noises, like the mic bouncing off my shirt, or even a rickety old air conditioner, were very hard to notice on the other end of the line. As a bonus, these headsets work in the headphone jack on Unibody MacBooks, for VoIP use.
I got these headphones and when I use the mic everyone says they can hear me loud and clear. Also the sound quality is amazing. I broke them in over 200 hours with pink noise and it helped a lot.
I think the microphone's great, especially the fact you get a little real-time feedback through the earphones (allowing you to hear yourself/your surroundings while you're talking).