The retail definately plays better for me than the demo.
I had everything set to high except post processing which was set to medium on the demo with 4x AA on DX10. If i set post processing to high then it would make the framerates so low that it would be unplayable with severe mouse lag.
On the retail i can use exact same settings but with post processing set to high, although i get framerate drops there is absolutley no mouse lag.... I do set post processing to medium though as the extra fps certainly make it more enjoyable at little effect on visuals.
I have said that i wouldn't buy Crysis yet but i gave in last night and glad i did, awesome game with awesome visuals....Can't wait to see what its going to look like in 12 months time when maybe we have hardware capable of running this at full whack settings at full framerates.