Veneers, try and be informed before you post stupid comments. I was deciding between Creighton and MWU-AZ, and will be attending Creighton. Good effort though.
Back to the OP's question and some of the other comments on this thread. I interviewed at Western and loved the school. As someone previously stated, Western has not yet graduated a class. This is a serious consideration; however, they have opened 20+ programs in different health professions, and each one has succeeded. They have initial accreditation, which I'm sure as you know, will turn into formal accreditation when their first class graduates.
Talking with current and former USC graduates is why I would suggest Western. They are graduating with higher amounts of debt because of USC's high tuition costs and the cost of living in LA (cost is one of the two major reasons why I am going to Creighton over any other school). Additionally, while I am not personally a fan of PBL, it can certainly cater to some people's learning styles. If that is you, that is great. The majority of USC students that I have talked with don't like PBL, but there are definitely some that do.
Here are the four year cost projections from each school's website (tuition, fees, living expenses, etc.)
Western- $340,000 (they only have their first two years projected, so I used the second year's budget for years three and four. Usually the fourth year will be substantially less because you're not there the whole year).
USC- $391,000
Fifty-thousand-plus dollars is a lot of money, especially when you figure in interest. In the end, you need to go where you think you will be the happiest. If that's USC, go there. If it's Western, go there. Wherever you go, you'll graduate a dentist, and most of how good you become as a dentist depends on you, not the school (which is why I think cost is so huge).
Good luck with your decision and congrats on getting in to multiple schools!