I've had one since last September, on T-mobile.
It's quite good, but would I buy one now, possibly not.
The stock ROM on the phones is pretty poor. Mine was slow, buggy as hell, and the battery never lasted a full 24 hours (with minimal use).
A few months back, I upgraded it to one of those custom ROMS, and the difference has been like night & day!
I now get 3-4 days of moderate use from it, it's really stable & touch sensitivity is greatly improved.
I use Memory Map on it alot which works really well.
The real problem with these phones nowadays is the underlying windows mobile o/s which is very dated.