Gnome has window overview, compiz has scale plugin, kwin has the window picker. Now you can get a window overview without the drag on system resources. Read about it here.
I think it comes down to chipset, I've also noticed it seems to be more problematic on 64bit machines. At least in my testing, which is just the machines I have available. I also don't care for how it cuts off the menu's of the program windows, makes it look half broken.