If your keyboard has Previous, Play/Pause, Next buttons, the way to get Expose to show desktop is to hold the command key while pressing the Expose F-button (I think its F4 - dont have my alum. kb here). Basically, Cmd-F4.
Anyway:
Likes: Expose+Spaces. Best thing ever.
Dislikes: (dis)connecting USB devices wakes up the computer
Likes: Spring-loaded folders and column view (press space bar to open immediately)
Dislikes: sometimes mounted devices show up in weird places on the desktop
Likes: Not confusing KB shortcuts. Most start with Cmd, followed by usually the first letter in the word, i.e Quit, Eject, Open, Reload, Tab, Window, etc. In less common ones you press Shift key, but the same letter remains, i.e go to Home, Applications, Computer, etc. None of this Alt-F4 or Alt-X-F (wtf) antics.
Likes: Clean design (software and hardware)
Likes: Doesn't require 8 TB RAM and 12 cores to run smoothly
Likes: No viruses to worry about
Likes: Dock
Likes: Menu bar on top (not in every damn window)
Likes: It works (no or very little troubleshooting that is easy to do anyway, intuitive)
Never switched to Mac though... I never had anything besides Macs