USC definitely has the reputation, but you have to ask yourself if that reputation+PVL+$4/gallonn for gas+nasty traffic is worth $500k. That said, it seems that they have recently starting changing their curriculum and things are looking better.
USN is in a great location, right near the freeway, and in a good area. There should be more than enough patients to go around since it's the first dental school in Utah. The COL in Utah is relatively low, especially compared to California. A major downside is that USN is not yet accredited. They will almost certainly be accredited, but the timing is a big question. If school starts before they are accredited, then you will be required to take out private loans, which will likely have a higher interest rate and require a cosigner or some type of collateral.
All in all, if I was in your position, I would be going to USN. They seem to be patterning their curriculum off of Western and Midwestern as far as integrating systems and concepts, which I think is awesome. Additionally, you can be there during the initial stages, which can be good and bad; good that you will be able to help form things, bad because you will experience the school's growing pains.
Good luck with your decision!