When you first see it you may think it's cool but I see it as nothing more than a dumb gimmick for two reasons.
1. Your monitor would end up smudged and need continual cleaning.
2. If you are on desktop 1 and would like to get to desktop 3 you need to scroll past either desktop 2 or 4. I'd rather just work as I do having access to any desktop from the taskbar buttons.
Ultimately it's nothing more than a pain in the ass way of working with virtual desktops. It also looks like some kind of crap Apple would bundle with their next OS but I see it's running on a linux box which is just sad if you ask me.