Pretty much every issue you blogged about has been fixed since you tried it out.
I’m running Windows XP with Pidgin Version 2.4.1. I do recall all of the problems you discussed in versions earlier this year though, so I think you were right on target.
Anyway, it’s worth a second shot.
PS, There was a major pro you didn’t mention: How quickly it starts and exits, especially compared to Trillian.
I’ve using Pidgin 2.3.1 on Ubuntu & on Vista at work.
I use scheduled tasks at work to start & kill(via script) Pidgin on Vista on work days, and it works great.
My kill script contains the following line:
No problems losing settings or logs.