The main thing is, everyone have their own preferences.

I'm a designer and I can tell that Mac OS X it's the best overall but I still use for Windows for other task that Mac OS X can't.

Conclusion, both of the OS are good but my preferences is Mac OS X is the best. (again, just for me)

Since this is a Apple forum, you guys should really watch this:
http://movies.apple.com/movies/us/apple/ge...ill_480x376.mov

WARNING! IT'S A MUST TO WATCH