Just installed the 90 day Windows 8 evaluation. I was extremely skeptical of the metro style, but my first impressions are very good. It's well done! One of my biggest concerns was that there wouldn't be a "typical" desktop. But there is, so if you really want to use that style (most likely best for working) you can do that.
I think of the Start Screen as just a new layout for the old Start Menu. After you get used to it, it's much nicer than the old Start Menu, since there's so much more real estate available…