Right now I'm getting the PS3 version mainly because of my friends, and I'm going to get the 360 later probably due to DLC, but it's only because I can (well, I hope lol) afford it. Many people don't.
If someone can only get one version, I'd say that if you care about multiplayer, go for the platform your friends have, if you only want the single player, go for the DLC. Tech reasons should come last because there are little differences. If I had to choose purely based on tech, I'd probably go for PS3 despite the lower res, due to the advantages you cited and most reviews I read gave the visual nod to PS3. The reviewers hadn't seen this thread though.