Switched from 8310. Better screen, was amazed at the differnce it made to me. Much "snappier" response when opening programs/surfing due to more internal mem faster cpu.
I like the keyboard, but is a little easier to mistype. Nothing that won't go asway as I spend more time with the phone.
The styling is much better. As I'm sure you noticed, lighter and sleeker looking. To me, the phone feels much nicer, more refined. I even prefer it over the iPhone.
I agree with the above post, if you liked the 8320 you'll dig the 8900.
~via smartphone mobile.rabroad.com~