Crysis 1 does not have AMBX support from the box but the developers from AMBX created a tool so some games (like Crysis) would work with AMBX anyway.
I play Crysis with an AMBX set, it just becomes way more realistic en fun. When you shoot the whole room lights up from the fire, when a grenade explodes you feel the wind from the explosion. You also feel the wind when running fast with maximum speed. When you get hit the rumbler also stars rumbling.
Here is a video where you can see the light effect http://www.youtube.com/watch?v=4CIg2ms_Lfg ( and http://www.youtube.com/watch?v=z6k5LQ2gdjk )
To bad that you can't feel the wind and the rumbler on a YouTube vid.
So it would be great if Crysis 2 would get AMBX support from the box. (or after some patch) If people make such a patch themselves it has always flaws.