Infinity ward actually said call of duty 4 is better on the PS3. They even said they had their best developers working on the PS3 version. That was the main hype for call of duty for the PS3, it was one of the first PS3 multiplatform games to look better on the PS3 finally. Games like rainbow six vegas were bad on the PS3 because they didnt know how to get the unreal engine 3 working properly on the PS3 yet. But that's changing since the actual unreal game, unreal tournament 3, works on the PS3.

http://www.psu.com/Call-of-Duty-4s-...a0001924-p0.php
http://ps3.ign.com/articles/690/690198p1.html

And I'm only explaining this because most people who aren't nerds and don't know much about games say everything looks better on the 360 without actually taking the time out to find out if it's true. I don't see why people have a problem with it, no one complained that xbox games looked better than PS2 ones.