Only a slight speed increase between opening those apps.
The real difference will be when devs write apps specifically for the iPhone 4S to make use of the better hardware.
Except this in the vast majority of cases wont happen as devs wont want to cut out everyone who doesn't have a 4s/ipad 2, think of all the iphone 4, 3gs and ipod touch users you would lose making a game for the 4s, the same thing happened with the 3gs and ipad 2, very few apps took advantage of the hardware.