I started using OSX after using XMonad for the better part of a year, and it doesn't even come close. Like vault_ stated, its simply to clunky. It takes almost a second to switch between workspaces, with a shiny and pointless animation. The shortcuts are hard to get right too, I still don't have a good one to send windows between workspaces (which I used to use extensively for keeping things organized and staying sane.)

I assume XMonad is a similar experience to Awesome--I never tried to understand Awesome too much. Spaces cannot compare.