Just built a new PC (desktop) and used Windows 8.
It's not too much different but it's just faster from all my experience, which is a good thing of course. It starts up ridiculously fast.
If you go 7 that's fine, but don't listen to the hate. It's way overboard, I don't get it. Anything you might miss from 7 or before (like the start) can easily be accessed or recreated. And as I said it's just faster.
I quite like the Windows screen too. Very customizable and more useful than the Start menu.