First of all, congratulations on being accepted to two excellent programs! You seriously cannot go wrong with either one.
I'm kind of in a similar "dilemma" as you, however I'm trying to chose between USC and Regis. This is just how I'm going through with the whole decision process, so take it with a grain of salt.
Two areas I've really been looking hard at are tuition/living expenses and location. Although I have the highest regard for USC and the PT program, I'm finding it difficult to justify spending $135k for tuition at USC. I'm not quite sure how much it costs to attend Columbia, however being an ivy league institution, I'm guessing it's comparable. I know Regis is around $80k for the three years, which is not too bad considering it's a private institution (just don't want to be in the hole that much after PT school). Also, you need to take into account living expenses. I know for both of us, it'd be a lot more reasonable to live in Denver than in NYC or LA.
Location also needs to really be taken into consideration. Remember, PT school isn't like undergrad. Once you're in a program, it's difficult to switch without going through the heinous application process again. I just bring location up because as an undergrad, I went to school for a year in Philadelphia and didn't like being there at all. Philly's a great city, but it ended up just not being for me. Anyway, I wound up transferring to a university in Nor Cal, where I should had gone in the first place. That being said, in my view, location is more important than many realize.
As of now, I'm leaning towards accepting the offer from Regis. I have to say that I knew absolutely nothing about the school and program before applying to PT school, however, the visit really opened my eyes. I love outdoor activities (snowboarding, biking, and hiking) and a more 'laid back' environment, so I know Denver will be a good place for me. I know in the end you'll make the decision that's best for you. Perhaps, we'll be classmates! We're both really lucky to have some great options to choose from! Best of luck to you!