UCLA is a better place to go when you factor in the cost, far and away. If USC gave you a scholarship to make costs even, I would make the schools about even, with UCLA prolly having the lead.
UCLA has a better location, better opportunities for research. USC has a better curriculum (lived with a UCLA med student last year, am an SC student. He and all of his friends kept saying how they got screwed by UCLA. Nobody has complained here). USC has a more social class (comparing UCLA class of 2001 vs. USC class of 2005 and 2006). USC also has a lot better clinical training, but at UCLA you prolly would have a better chance to use state of the art equipment.
So if I had a choice of choosing between the two, costs being even, UCLA would win.