Being a BES Admin for the 5000+ user company I can say I have had every single BlackBerry released, all the way back to the 850
I am not a holster-type IT guy; I like a device that fits well in my pocket. When I tried the 8800 I was using a Pearl. The size alone killed it for me. The only redeeming quality for me on the 8800 was the GPS. When I stopped to think about how often I would actually use the GPS, I decided to give it to somoene else in my company. The 8800 was just too damn big to go in a pocket. Other than that, it performed like any other 8xxx series device. The keyboard was a bit too cramped as well, but it was do-able.
I received the 8300 day after launch and I am pretty impressed. As I said before, the thing that matters most to ME is the ability for it to fit comfortably in my pocket. The 8300 is on the borderline. It fits, but its still a smidge too big. But the new features like full screen video, spell check, 3.5MM headset/headphone jack, and better camera make me try a little harder to make it work.
I still may go back to the Pearl for its size (I have no problems with SureType), but the 8300 definitely works for me as well.
Hope this helps,
Greg