I love the skin. Installed it over the weekend and have been really digging it. I use both a PC and a Mac so I'm equally comfortable with both. I think OSX beats WinXP hands-down for UI, so this is a great suite.
Oh, and after a while, I found myself trying to hit command-Q to close applications on my PC instead of Alt-F4. That's how convincing it is!
Why do I want an OSX skin on my Win box? Because I love the UI for OSX, but want the functionality I'm used to in a PC. It's like having a Mac that can run EVERYTHING. Even though it's not really a Mac, it creates enough of the illusion to fulfill a long-time computing dream of mine
My only suggestion would be to make the buttons on the taskbar for each application more defined. As it stands, there's no clear line between them. Maybe making them bubbled or something like chat window buttons are in MIRC for example. Just something to clear it up visually.