I played it on Ps3, looks good Imo

Looks fine on either system, though the PS3 version showed noticeable lag in certain spots, but nothing detrimental to gameplay.
 
Source: 
http://www.gamespot.com/features/6242816/index.html

Aside from the graphics difference (mostly color pallet) it looks and plays the same. I have played both versions and the only difference I saw, performance wise, is that the PS3 had more screen tare then the 360 version. As far as graphical difference is concerned then while the 360 version has slightly better textures then the PS3 I found the PS3 version to be more appealing because of better mood lighting and the fact that for some reason the 360 version looked a bit hazy to me. 

i heard he screen tearing can be unbearable if you have multiple save files but othewise it good,

I played it through to platinum completion on PS3 and have 940/1000 on 360 and I can say I noticed no major differences. There are slight differences with the lighting that I noticed (in the PS3's favour), but the screen tearing was fairly minimal on both and I can't say personally there was a ton more in the PS3 version (although lots of people seem to have had this issue).
 
I'd say it's comparable enough on both platforms that you can comfortably buy it for whichever you prefer.

It looks fine, I've had issue with trophies on the PS3 (not sure if the 360 has achievement problems).  My trophies for finishing chapter 2 and 3 never registered, which means I have to play through the game again just for those two trophies, really obnoxious.

I just got it yesterday, and the graphic issues are the only real difference. If you are a graphics whore or a really picky person obsessed with perfection in visuals, it will bother you. When you are running, it looks fantastic. When you try to look far away, you can see that the draw distance is not as good, screen tearing can be annoying, and pop in occasionally happens with framerate dips. If you're just in it to enjoy it, this will not get in your way.