I got into all four and it really depends on what you're looking for in a school. Here's my take:
UCLA- I think you should give it a shot, because in the off chance you get in, you'll get in-state tuition! Also, they favor their instate applicants, so that's a plus. Decent class size (88), prestige, P/F/H grading system, quarter system! I came from a quarter system undergrad so that was big to me, plus tuition!
----> UCSF is also a state school that'll be cheap if you can move to NorCal for four years.
LLU- There are mandatory religion courses that are taken alongside the dental courses, and there are things like no caffeine, no meat, etc. that you are expected to abide by. To me, these weren't issues at all because the environment here was exactly like the environment I was raised in. Everyone I interacted with was super friendly. If it wasn't for UCLA, I honestly would have attended! Decent class size (~100), well-known in the SoCal region, graded (if I remember correctly), and quarter system.
USC- Applied as a safety school. The campus and facilities are
gorgeous, but the tuition is somewhat ridiculous. Students were really enthusiastic and outgoing, and of course it is a huge class size so there's a lot of different things going on at a time. The rivalry with UCLA is also amusing
Thing here is that there is a problem-based learning (PBL) curriculum which I didn't like at alllllll. I prefer traditional lectures... Large class size (144), well-known, can't recall grading system, and trimester system.
Western- Lived close to the school so would have commuted if I attended. The school is nice but seemed like it was in the middle of nowhere, like it was in a really deserted area (maybe it was just on my interview day?). One thing I really liked about the school was that it has a virtual 3D table for Anatomy/cadaver dissections, so you have access to it all day as an app on the iPad they issue. It's like a state of the art program that is comparable to actual lab. Smaller class size (64-69), graded, and semester system.
tl;dr: Personally of the three, I would pick LLU because its integration of religion/certain principles is well-known in the SoCal region for producing excellent doctors who take a holistic approach to treating patients. Also, I believe when you take tuition, fees, and living into account, it comes out to be cheaper than the other two.
Hope this helps! Good luck!