This is really a "to each his own" subject. I spent some time playing with the 8800 before going with the 8300. Coming from a Treo, I must say that I much preferred the 8300 form factor. It's shaped sort of like a thinner Treo and the keyboard is an improvement over the 700p IMHO. On the other hand, with the 8800, I was very concerned that I'd never get used to the keyboard.

After 4 days with the 8300, I'm very happy. I haven't seen any lag issues, call quality has been excellent, the camera is acceptable (certainly better than the Treo's), and email is working well.