I don't like it, but for me it doesn't matter because I have system restore turned off on all my computers (at it's best it makes a slight mess of your system - at it's worst it makes it a lot worse, so I rely on full image backups instead), and if you have system restore turned off, you get a question box from the WM installation and can cancel the install!
As for Vista I ran it for a couple of months but got sick and tired of the thing that's gonna be the buzzword in 2007: WWW. No, not World Wide Web. I mean World Wide Wait!
Even with a rather sharp computer, like the laptop I ran it on, some things are horribly slow, and others are just downright annoying. I want to decide what kind of protection I need against myself, thankyouverymuch! So in 20 years you'll see me as the world's last remaining XP user...