I've been using Gaim 2 for a few days now. It is still in beta. It is really an improvement over version 1. The interface is much nicer and it feels zippy.
by far the biggest improvement is that you always see your own status; all in all the status system is greatly improved. It's also nice that you see your avatar in beta4.
It's a nice improvement over gaim1, which was a nice IM anyway.