Been playing the 360 version for about an hour now and yeah, big difference in quality vs. the PC version. Textures are alot muddier, it has screen tearing (not horrid, but evident) and it has a weird darkness to it when you turn the camera. When I turn around really quick, it is much darker for a quick second, then it lightens up. It is like a TV that has a black corrector mode or somting similar. My TV does have these fucntions, but I have them turned off. The PC version does not do this. For example, when looking up at the Sky and then looking down, the screen is very dark for split second, then it lightens up. Very weird effect.
Frame rate seems pretty stable at 30, but you can definately tell it sure does drop. I thought textures were a blurry mess in RAGE up close, but the ones in this game takes the cake. There are blurry textures even when not up close in some parts.
Overall, the 360 version is not bad, but anyone that has a decent rig, I would highly recommend getting the PC version of this game.