Definitely some changes to the scene. Not sure that it's necessarily better, just different, unless someone can point out some specific tech reasons.
Is it possible that the higher res textures plus superior texture filtering is responsible?
It almost seems like the same details exist in the other versions but are smoothed over by either a lower res texture and/or filtering.
http://www.neogaf.com/forum/showpost.php?p=247030834&postcount=160