I'm a first year at USC and I think this school is great. The cost is higher, but with the opportunities available in the hospital, I feel that I'll be more prepared for residency. Although I haven't done any rotations yet, I have enjoyed the ICM part of the curriculm; it's nice to actually see patients rather than spend all your time in class. I have also followed the trauma team around and actually participated in patient care, including surgical procedures.
Already, I have a publication this year on a study on pediatric trauma and I have a project lined up this summer to work on a revolutionary HIV gene therapy drug. I'd say research opportunities are great here but you need some initiative to actually email the right people; no one is gonna just do everything for you.
Yes parking is a issue, i've never had any difficulty getting a permit (unless of course you want the special parking structure permit) and I always wait till the last minute for those things. I do think this is a minor problem and it should be fixed; however, parking wasn't a critical thing on my list of criteria when deciding on a school. I came from a UC undergrad campus that had worse parking conditions than here so this isn't a problem that's exclusive to USC.
If you want amazing clinical experience and like hands-on learning, then USC is a fantastic place. If you want research, we have that too. It is expensive and the price isn't likely to go down, but with the increased cost of the UC's that is becoming less of a factor (I actually know some UCLA folks that say they face a $150k-200k debt after school!!!) It's an important 4 years of your life, make sure you decide carefully on where you want to go.