If you are comparing catch up PC games will always be playing catch up to consoles,SOME games not ALL might look better then a PS 3 but that doesn't mean that a specific game will look better then an exclusive that was made for a ps3.
I honestly can't remember playing a game that was available cross platform that was actually better looking on the console than it was the PC.
Besides, current gen consoles can't even support Full HD. PC's go above and beyond Full HD.
Even if you a took a game and made it exactly the same for the PC as it is for the console, shitty resolution, no graphics options, just like for like the same game. It would still look better on the PC because the graphics cards can apply anisotropic filtering, Tessellation, and all kinds of other shit I don't fully understand