I bought these and when I plugged them into my PC, the microphone was horribly low - no one could hear me despite the microphone was right next to my mouth. The solution is to go into "volume control", press "properties" on the microphone tab and select "mic boost" - the sound is wonderfully crisp and clear.
The cord is 2 metres long so it's very good if you wanna listen to music and cross the room to go and get something. The only thing letting this down is that at first it is a bit heavy on your neck and irrates your ears a tiny bit, but otherwise its a pleasure to use!