I'd say it was a bit of a pain re-learning the layout (Using the "start button" for example, or even looking for MSPaint) but overall you can navigate your way through the OS pretty efficiently, especially if you have a nice touchpad and use a few shortcuts. The only real problem can be cycling through apps (Adobe Reader, Image viewers, etc.) but even that isn't a REAL hassle. It's just a matter of getting used to it, and once you do, I tink it's just as fast, if not a little more fluid. There are also one or two points I like about it, stylisically. The way the new windows are designed graphically is pretty neat, and the color scheme is rather pleasant and even adapts to match whatever screen background you select. Beyond that, it runs well all the software I need it to so I can't complain.
Don't get the big fuss here...