One thing to consider - Gears of War 2 is probably as good if not better looking than any shooter game on either system. It achieves this by sacrafices made with a DOF (Depth of field effect) So while it 'looks' better it doesn't make it a better technical achievement its a better design achievement. Uncharted is similar to this, it looks edit: great but its not the best technical achievement on the PS3. For different reasons.
So while RFOM 2 might be better technical achievements I would nudge Gears of War as the better design achievement. Depth of field works by obscuring the long distance detail in favour of whats in front of your face. Its a bluring effect. A design sacrifice that is made as a trade off as the often masturbated "console optimizations" often are. So I would pick that RFOM 2 is probably technically better just like GTAIV is technically better on the 360, the average public will probably pick Gears of war as the "better looking" just as the average punters picked the PS3 version of GTAIV as better looking as well.
Btw, don't raise your hopes on KZ2 yet, it employs DOF more heavily than gears of war.
Tease.
