The screens pictured below are originally from Kotaku (www.kotaku.com), but have been cut-away for your viewing pleasure. The difference is stunning. Each image is linked to the larger 720p file.
The first screen is perhaps the most peculiar. Not many polygons or textures to render but still a noticeable gap between the two.
There are multiple tells in this image. The enemies and environment appear to be jagged and pixelated. It would appear that Square Enix have taken Microsoft lifting the Anti-Aliasing mandate almost one year ago to heart. The shadows are worse on the PlayStation, but that is hardly a trade-off.
Wow. What can be said about the contrast in the third example? It’s almost as if the 360 version is being upscaled apart from the HUD.
This is where the Xbox360 does a bit of catching up. It is closely likened to its counterpart, but the color in the textures just lack the “pop” of the PS3 iteration.
All in all, PlayStation3’s Final Fantasy XIII would seem to be vastly superior visually and if you factor in the uncompressed FMV video/audio, it’s the only show in town. Unless you simply own an Xbox360, that is.