If entering Mission Control (ctrl-up) is taking to long you can speed up the animation entering the following in the Terminal (/Applications/Utilities/Terminal.app):
defaults write com.apple.dock expose-animation-duration -float 0.2; killall Dock
To disable the animation altogether :
defaults write com.apple.dock expose-animation-duration -float 0; killall Dock
I prefer to have a fast animation rather than none as it provides context, it shows me where the applications are coming from on the screen.