I downloaded and installed the Windows 7 beta this March, and was pleased with it. I like the U.I. and the "increased productivity" it provides, but mainly its "dock" buttons on the toolbar. I felt at home because it had many similarities with Vista, though I didn't see a huge performance improvement.
However many of my games, especially the Project Reality mod didn't work on Windows 7, so I reinstalled Windows Vista again, happily enjoying my war sims.
Maybe I'll get it, but I don't see any killer features or improvements that would make me want to spend a lot of money to upgrade to an OS that isn't hugely improved.