Mission Control has been horribly slow on my 2011 MacBook Pro 15" (2GHz quad i7, 8GB RAM, 256MB graphics, SSD) -- swiping up usually freezes the screen for 2 seconds, before showing me the Mission Control layout. I've tried switching to discrete graphics only, but the problem doesn't go away.
It seems others have been experiencing this, too, and it might be a video driver issue. Has anyone found a fix for this? One MacRumors forum post suggested disabling automatic scrollbar overlays, but that hasn't helped.