Windows 7 is generations ahead of Vista in terms of performance, stability and doesn't have a pop up window every 5 minutes asking you if you're really sure that you want to do that
The first thing i did after installing vista was turn off UAC.
I like to think of it as more refined, polished Vista with better features.
7 = Vista with a few code optimisations and the default security settings changed a bit.
7 is great, so was Vista. Unless you were trying to run it on an early 2000's machine with 256Mb of ram.
However, if i can squeeze extra performance out of windows 7, which it seems i can then I'm happy to upgrade.