It's been a while since I used Unity, but as I recall it uses a global menu (yuk), it lacks a window list (which I like), and Alt-Tab works in a per-application

It's been a while since I used Unity, but as I recall it uses a global menu (yuk), it lacks a window list (which I like), and Alt-Tab works in a per-application, not a per-window, basis. And I think it does the Mac thing where clicking on a launcher icon either activates the app or launches it. I generally want the launcher icon to launch a new window, no matter what. It's also, IMHO, ugly as heck out of the box.