At least the new client no longer feels like it was written by a bunch of monkeys in Visual Basic.
The new UI doesn't bother me too much. I appreciate the added info in the "shift+tab screen". Additionally the new games list actually keeps things sorted in alphabetical order unlike the old one which would resort by... what criteria? Anyway, it never kept the games alphabetized.
Number one complaint: Valve still hasn't implemented a way to group your friends in the IM portion of the client. I would love to be able to shuffle my friends into different groups to make them easier to find. It's really a pain to have to shuffle through 200+ names to find the one person I want to IM.