For instance, in Windows and Gnome I can hunt through menus with the keyboard by simply press ALT and then the underlined letter of a menu (then use the arrow keys to look around and press ENTER or SPACE to pick one). This is consistent throughout those environments but on OS X you can't navigate like that, you have to memorize 2,000 hot-key combinations. Microsoft kind of ruined that nice feature with the "Ribbon" but the new keyboard navigation system for the ribbon is still more logical and consistent than what I've seen with OS X.
That's why I like to just put my Unix dev environment in a VM on Windows. I get the best desktop experience (for me) and when I need it, I have Unix.