Use the one you are more comfortable.

We jabber.iwethey.org is v1... and it is stable. Never segfaults, aborts, looses comms etc...

I've seen some reports a while ago about it just exiting without anything useful... but I believe that was v1.99.something or Alpha stuff.

To me, The choice is simple, I'd use v1 mainly because I know it better. V2 might just be up your alley.