I use it, and it's great. But if you're going to use it, I'd suggest buying the full version. The last time I used to the free version... well, it sucked.
I've been using Trillian for over a year now, and I'm happy with it. You won't have all the advanced functions that the individual clients have, but at least you'll be able to have ICQ, AIM, MSN, Yahoo, and IRC all in one program.
It'll take some getting used to when you first try it, but you'll probably grow to love it.
