The shadows in the XBOX 360 version are not better, they're just unrealistic (like EdibleFood said there is some global illumination missing) and way too bold. Also the geometry varies slightly from the PS3 and PC because it is allot less smooth which makes it look unrealistic (I'm not saying there are no such things as rough shape in the real world but you get the point). One more thing, I noticed the textures on the XBOX 360 version are less detailed. This is what I noticed first in the graphics comparison (besides the "shadows").
Ka-BaMf's comments