There is now an actual power button instead of the 5 step thing you had to do previously.
You can get to the taskbar from metro apps.
You don't have to spend ages sliding the mouse up and down to close a metro app.
You can pin metro apps to the taskbar.
These are the only changes I've come across so far, all of them good things. But my opinion stays the same, if you have windows 7, don't bother. If you have anything else (that is windows), then upgrade, the start screen is a good move, it's like a really big start menu.