This really bothers me too on an air where I'm switching back and forth from fullscreened terminal to browser constantly. Fine, it looks an feels quite cool when combined with a swipe, but it's really sluggish when you switch with assigned keys instead..

On Lion machines, using the keyboard shortcuts (ctrl/cmd+1/2/3/4), switching spaces is well under a second (my guess would be 500~750ms). From MC (which takes again less than a second to enter), entering a space is more in the 750~1000ms range but still, I don't know where you get that 2~3s figure.

This may help, although I found too fast an animation makes me dizzy after a while.

    defaults write com.apple.dock expose-animation-duration -float 0.15; killall Dock

That's the mission control expose animation, I know of that and use it. I want the four finger swipe sped up. I don't know the absolute numbering of my spaces, it's a relative association for me.

> I want the four finger swipe sped up.

Ok, I never use that one. Sadly it seems that for the sake of consistency with the physical world this animation is tied to the movement of your hand (whereas the MC exposé swipe is a trigger).

> I don't know the absolute numbering of my spaces, it's a relative association for me.

One can set up "Move Left/Right a Space" shortcuts in the Keyboard prefpane. Same animation speed as the swipe, which feels ungodly slow.

I haven't tried the GM but on DP4 it felt like the animation takes even longer than on Lion. It moves at the same speed but the 'settling' time when it's slowing down is much, much longer. I'm talking half-a-second-longer longer.

Being unable to cycle through windows with tab in exposé is what really hacks me off about Lion at the moment.