I was in the same boat a few years ago and went with Pitt after attending undergraduate at Minnesota (cost was equal). Having been to both schools/cities, I can assure you that there's no wrong choice here - they're both fantastic places and you're going to have a wonderful time at whichever you choose. If you have any questions about either campus/city, I can try my best to give you an (unbiased) answer. I can also answer questions about Pitt's curriculum, but not Minnesota's.
Things to consider when making a choice (assuming money is equal. If one school is way cheaper, obviously go with that one):
~~~ Transportation/proximity of things (Both schools seem to be about the same distance/time from grocery stores+Target. Minnesota has the Light Rail from Riverside, Pittsburgh depends mainly on the Port Authority bus system. Not sure what else you'd like to know about. Ask for specifics and I can provide answers.)
~~~Weather (Not going to lie, the weather in Pittsburgh beats Minnesota hands down. I do NOT miss walking to class in subzero temperatures.)
~~~Apartment/living (For Minnesota, consider looking at apartments on West Bank, it'll be cheaper than all of those ridiculous "luxury" apartments that they've been building. Seven Corners apartments would be my recommendation, dirt cheap if you can get in (rent for a large studio was ~650$ a month) +20 minute walk from the dental school. For Pitt, Oakland is most convenient for the school, I don't have specific apartment complex names off-hand but can ask around if you're interested.)
~~~Use of SIM clinics (Call and ask the school about this to confirm. Pitt uses theirs for several courses (amalgam/composite/endo/crown+bridge/etc) and has course instructors present to look at work, provide feedback, and manually grade it. If I remember correctly, Minnesota uses theirs in a more limited fashion and has a sort of camera thing that provides digital feedback/grading. It's a matter of personal preference, really.)
~~~City (Twin Cities area is smaller and more concentrated (Nicollet Mall, MOA, MIA the stadiums, and the arts district seem to be the main attractions). I personally felt it had a homier/cozier feel, which is really nice if you're not sure you're a city person. The Minnesota campus is more self-contained, but it's also a very, very large campus compared to Pitt. Pittsburgh is around the same in terms of overall population, but the city feels a lot bigger and it's a way, way livelier place. There's a lot more to do (shopping, amusement park, zoo, theatres, parks, gardens, stadiums, and it's way easier to get to any of these things at a given time. Pitt's campus is not self contained and blends in with the rest of the city/CMU. Better for if you like being in urban areas.)
~~~Clinic access (Can't speak for Minnesota's policies on this one. I would call to confirm. Pitt has its students start in clinic right away (first week of class) observing/assisting, which continues through second year. During the summer of your first year, you will also be seeing your first patient to provide a prophy. Actual clinic begins 3rd year.)
~~~Boards (Pitt has students take the NBDE Part 1 during the summer of their first year, Minnesota waits for second year)
Final note: Pitt does offer a hefty number of academic scholarships and seems to wait to notify you of eligibility until after you accept. Not sure why they do this, maybe they want the choice to be based off of the school rather than the money? IDK.
My recommendation would be to accept both for now and see how you feel after a few weeks/finding out about scholarships. It's not much money in the long run and you'll feel a lot less stressed if you can take your time and weigh your options as opposed to deciding right away.
