The screen is very nice and the data service is fast (EV-DO). Call reception is good and I've only dropped 1 call in the past 5 months. It is very extensible, and has a lot of features. Camera/video quality is decent. It is a well made, solid feeling phone. It has bluetooth, EV-DO, and infrared for file transfer.
It is very sluggish. Even with registry tweaks, the phone just isn't that reponsive. Sometimes it takes several seconds before it starts dialing a number. Windows Mobile is buggy and crashes with some frequency. The battery life is quite poor, even with moderate use I'm lucky to get more than a day out of it. The keyboard layout takes getting used to.