These people who say "Imagine if you had that extra 150,000$ difference, you could have a luxury car with that amount" are ridiculous. When your loan money + interest capitalizes when you exit school and you start paying interest on your interest, it will hit you, it is something you have to pay back. Every month. Conversely, a lump sum payment would never just fall into your lap for you to buy a luxury car (normally). Your loan money is actually a lot more serious than a comparison to a car you could buy with it.
It might not seem too serious now, but when you start to have a family, save for retirement, open a business, buy cars and a house on loan, etc, you are going to want the lowest monthly payment possible on your dental school payment. You can have good memories anywhere and good friends anywhere, but I would argue no one sits at home and are glad they went to the most expensive dental school with the best weather and nicest clinics. They are going to care about taking care of them self and their family.
"Loan money is not lottery money"