The most noticeable difference is the higher resolution of the screen. Documents that I enlarged on my Pearl I couldn't make out the fuzzy print now they are readable. The camera is way better. The OS is also better but the 8320 is pretty good too (my wife has that). Yeah, you could wait a decade for a 3g Tmob phone but you could be dead by then too
Personally I think 3g is overrated. I use WiFi most of the time and when I can't stuff shows up fast enuf for me.