I got the opportunity for a free upgrade after my Santa Rosa MacBook Pro went kabook for the second time and was going to be yet another expensive repair (gotta love John Lewis's free 2nd year warranty ).
What made we want to upgrade to it then rather than just getting a classic replacement? The unibody obviously, much much stronger. The 4 finger gestures (my old MBP only had two finger scrolling), the faster FBS and RAM and bigger hard drive.
Oddly enough, the glossy screen I thought I'd hate it, but I've gotten so used to it that I see a matte screen and it just looks so lifeless.
But don't get me started on the buttonless trackpad. Fecking pain in the arse.