mIRC is an internet relay chat. As in typing.
Can you talk, DJ etc over it? Yes.
But judging how he said he use's team speak.. yeah I wouldn't be on mIRC much either.
Team G3 use's straight ventrillo, we also have an mIRC room.. and we only have about 2 people in it, show's you how much we use it compared to our ventrillo which has about 20 on all day.
Teamspeak/Ventrillo > mIRC
...
btw, i've been in your mIRC a few times, and it is lonely, I end up leaving it after 10min.