I have WWE 12 for PS3 and 13 for 360. I can confirm that WWE 13 looks much better than PS3 WWE 12. So if you think WWE 12 and 13 look same on PS3, then it is confirmed that WWE 13 on 360 looks much better than PS3 version.
Erm, the lighting effects of WWE12 and WWE13 are completely different. You cannot compare WWE12 on the PS3 with WWE13 on the 360 and say the 360 is better when it's completely different.
That is why I said that if people think that WWE 12 and 13 are same graphically on PS3, then I can surely say 360 version is better. If not, then I cant comment because I dont have PS3 version of the game.