The problem is that finder sucks compared to windows explorer. I've used mac os x for two years now and I still do most file management tasks via command-line. This is not the case in windows and linux, where file managers are usable.

I don't like ribbon ui at all, though. But for newcomers it's probably going to be an easier way to manage files. Small anecdote: my grandmother had never used a computer until 6 months ago. One of the hardest things to explain to her was windows context menus. With buttons in the ribbon it would have been so much easier.