Mahya,
Congratulations on this wonderful dilemma of yours! It is a great feeling to have to choose between two good options.
My advice would be to go where you feel you will enjoy dental school the most and which school will help you to acheive your career goals. ASDOH is a chill place to go to school. The atmosphere really is like you saw during your interview. No where else I interviewed was anything like it. On the other hand, specializing COULD be different here. With no history, no one is really sure how residency programs are going to view our applicants. Could be positive or negative, but no one knows for sure right now.
ASDOH's clinical exposure is great! The D3's are doing more dentistry than a lot of other schools get. I can't wait to start (my first patients are in June...). Also, there are a lot less "kinks" than might be suspected. The inaugural class has had some serious flexibility training because every day for them is a new day...never done before. Our class (Current D2) got a lot improvements and the current D1s are still being fine-tuned. I would probably dare say that your incoming class will have different kinks than other dental schools, but probably not more or less than any other dental schools because after three years of predecessors, they have really gotten the curriculum to a great place.
The D2 year is so much nicer with NBDE part I behind you. I am so glad I don't have to study for that still...
Also, money is money, but it's not everything. I would actually expect the difference in tuition between ASDOH and USC to be smaller than you have calculated. ASDOH is not cheap and it is getting not cheaper every year. When the current D3's started, their D1 tuition was less than $30,000 a year and now the new D1 tuition (For your incoming class) is a squeak under $40,000 + fees. I'm not sure if the new tuition has been communicated to everyone very well. My guess is that your calculations are based on a $36,000-ish number you got at the financial aid part of the interview (the Board of Trustees just approved a tuition hike). Just a thought, because the difference between $250,000 and $330,000 for school probably shouldn't be the deciding factor in my opinion.
As another thought...Arizona is probably not going to be the Mecca for new dentists that it has been in the last few years. Although the population is growing rapidly in Phoenix, hundreds of dentists moved to Arizona last year. With some ASDOH graduates staying, with some Midwestern graduates staying and with every graduating dentist at other schools talking about how great a place AZ is to practice in I would expect the demand for dentists in Urban Arizona to cool off in the next ten years.
Oh yeah...no beach in Arizona...except for a country song...
Good luck with your decision. If you PM me with your phone number, I would love to talk to you and answer any questions you may have that would help you in making the best decision for you.