really odd situation
it uses AMD's TressFX 3.0 and NVIDIA says it will have VXAO (some new AO tech they have)
To be honest anything would be better than the AO Crystal Dynamics used in the Xbone release (well apart from Far Cry 3's wacky take on AO). Something, something Ambient Obsucance I think they called it. Not particularly accurate and wasn't very tight to the geometry that there was a visible halo on most objects (there's a chair in the title screen where it was massively obvious). Pretty stable though and no flickering or clipping that you can normally see in cheaper implementations used in some console titles but that's not been a problem on PC for a while with various methods available.
Isn't VXAO what they used in that Moon Landing lighting demo they put out when Maxwell released? HBAO+ Ultra in Syndicate is currently the muts nuts as far as AO implementations go from what I've seen first hand so should be nice to get something new to play with.