More major differences:
Media - There's a "View Memory Use" feature that shows u how much media ur using and on what...
Pictures - Use trackball to go from one picture to the new by scrolling left and right instead of having to click N or P (which u can still use)
BBM - Refreshed looked pretty much...
Browser - Is faster but in this BETA OS it goes to Media Net when you open it (a bug) so to use the browser u gotta use "Go To..."
So far so good for me using this OS