Both those programs have big plusses and minuses - I have spend significant time both programs.
UCSF is a good all around program, the residents are good people and there is a fair balance of op/non-op learning. But, there are some really malignant attendings. One of their recent graduates (2004) actually failed the boards - this is someone that was highly regarded in the program. I am sure they are not advertising that little fact. And for a big research school ther is no protected academic time/rotation. Frisco is a cool place.
All the rumors about UCLA are absolutely true. One of the chiefs told me to "come to UCLA if you want a laid back L.A. lifestyle and don't want to work hard." They do very well on tests and can quote you studies on how to scope a monkey's butt, but most are sub-par in the OR. L.A. is a cool place.