UCSF all the way.
USC doesn't even interview the potential 95 applicants that will ultimately spend 3 years and $127,000 in tuition alone. Again, that's a class size of 90-100 students, where UCSF is around 28-35. As you've already experienced, UCSF provides a thorough interview day on a Saturday to meet students face to face and allow students the opportunity to get a real feel of the program. Any school with a ton of money can pay to be ranked #1 in the nation, but what does that even mean to anybody? It sure doesn't mean anything to most employers. Read some posts on here about student debt after they graduate before submerging yourself in fantasies of everyone "ooing" and "ahhing" over a USC degree. I know you're not concerned about tuition, but isn't that a huge part of life after graduation? UCSF is a very highly respected medical center, in the awesome urban environment of the bay area, and it's nearly half the price tag.
Both schools are heavy into research too, if that's your thing.
--my opinion*
If you LOVE LA, and tuition is not a factor at all then I'd say USC.
Honestly though, I'm sure USC grads are happy to promote their school, but I'd say UCSF is 10X more impressive, even if it's just because they accept 28-35 students instead of 100.
*My position is biased towards SF because every time I hear USC mentioned for PT school I cringe at the debt burden that people inflict on their lives.