As for me, I rarely use the mic. I guess I am just old, but I feel kinda retarded talking into a mic'd headset while playing. Something about it just feels weird to me. I know it's no different than talking on the phone, but to be fair, I hate talking on the phone too.
FWIW, I am an excellent listener and a very fast typer. Sometimes I'll type more in party chat than the guys with mics will say. So I am good with the party communications when it is necessary.
The biggest problem I have with the mics is that half the people out there have no business using them. The mic is either too close to the mouth or too far away. Can I get a mic check please?!? Oh and the people who use hands-free mics while there is a party going on in the background...just stop playing for everyone's sake. :P