As recent switcher from Windows, I think the Finder is underpowered compared to windows explorer, for example you can't pause a file transfer.
Another thing I don't understand why it's not possible in OS X is cicle through options in a pop-up window, for example when you delete a podcast in iTunes and the program asks to keep or delete the file.
However the stability of OS X is better compared to Windows, the apps look and feel better (I hate the Metro interface in W8).
Mostly I'm just amazed how much can I do with mission control and the different spaces, when I have a dozen of open windows I can move through them easily and fast. Also quick look is amazing.
use tab to switch between options and space to select an option...