I was impressed how easily my system upgraded without a hitch.  The only incompatibility was with ATI’s CCC, which it happily disabled.  System response feels much snappier than before, but I am running it on a quad with hyperthreaded 64-bit edition with 6 Gigs of RAM. 

The first large change is the start menu.  Quicklaunch is now gone; however, in a way it was combined with the tasks running.  As before you can create ‘quicklaunch’ icons on your taskbar, but these also double as an indication there is an open window.  It simply has a box around it, up to three.  When you hover over the icon, a small-preview of all windows with that task type are opened.  This includes multiple tabs in an IE session.  There is a way to add quicklaunch back, but it’s a little complicated.  Let me know and I can send you the instructions, but I think you will learn not to need it anymore

I miss Dreamscene; apparently the feedback was it was a feature that took up processing for a low-res moving desktop that was never seen.  Since I run multiple monitors, it was nice to have this moving background.

My system has been rock solid since I installed it, and performance is much improved.  Perhaps Microsoft got it right this time?