So far so good! I am impressed with the performance increase and happy to report an extra hour and a half of battery life!
Had a few minor issues, but were all taken care of when I ran the setup as Administrator or turned on the capability mode.
I am not sure that I like some of the new icons, the Microsoft Media Player one is completely different. I am used to finding applications by their icons, but I guess it's not that bad of a change.
If you have a chance to get your hands on the RTM products, give them a chance. That machine of yours that ran Vista RC 1 slowly will probably handle the RTM noticably better.