I tried it on my laptop a few months back. While it was very annoying at times, it was also very interesting. It was actually kinda fun learning the new OS, and I thought it was pretty cool looking. But eventually I became frustrated, as the new control panel (I forget what it's called- I think it's just settings now) and it was very limited. Also the computer tried to mimic the way Android multitasks, which is a big no-no for a desktop OS. I couldn't even figure out how to use the new IE, and I couldn't even use my own picture as the wallpaper for the start screen. And there is no way to disable Metro, and the desktop no longer has a start menu. Although, on the positive side, it was really fast, and it looked quite appealing. I thought the new start screen was fairly easy to navigate, and I can totally see the appeal of it on tablets. I could even see it being really popular on netbooks with a few tweaks.
It's pretty clear to me that MS is trying to create a rival for Android for the tablet world. And I believe that in the near future, Android and iOS won't be the only mainstream tablet OSes. But as for the full-size laptop and desktop world, I would stick with seven or vista.