I really dislike the new interface.
It seems that I know have to decided between viewing my contact list and viewing a conversation. I also can't see all my online contacts broken down in the groups I've created, I have to click on each group to see online contacts within that group, or I have to view ALL online contacts.
I don't see any preferences for changing how conversations/contacts are displayed. :-(
The group video calling might make it worth the annoyance of the new ui.