every time I pick up a Blackberry, I never seem to be able to get comfortable with the UI.
Due to my job change I'm finally switching phones/pdas/carriers. I'm on Cingular now, and picked up one of these for my "phone."

Smartphone running WM5. I've gotten it to sync with my Mac via Missing Sync (over bluetooth even), but haven't gotten push to work yet (the imap client works though). A few bugs and I still worry about trusting my calls to an MS OS, but no show stoppers yet.
The Treo650 will be replaced by one of these as soon as they come out...actually by the 8525 which is the upgraded 8125, faster chip, 3G capable
So I'll give WM5 a try. Some things are cool, but other things are ridiculously convoluted. But such are most OSs...