If your sole goal really is to go into JAG then accumulate as little debt as possible. However, I think very few people stick with the original law school plan, so be wary of that.
Then assuming everything else is the same any law student should consider location, cost, personal feelings about the school and last at least U.S. News Rankings.
Obviously New York and North Carolina are two very different places, additionally NYU and Duke are two very different schools. If your in to college basketball and living in a College town for three years Duke will be awesome!
If your into going to Broadway plays, shows, Central Park, etc NYU will be awesome.
I personally would like the Duke experience, but I love basketball you may hate it. Therefore, always remember that choosing a law school is a highly personal choice, and random people on the internet should not be the basis of a life altering decision.
Your clearly very intelligent to have been admitted into both schools so do not overthink it to much.
If I was you, which I am not I would choose the cheaper cost of living, scholarship, and less stressful environment of North Carolina, particularly if you really are planning on going into JAG, because they will assign you a location so your connections in law school will not matter that much.
This is also a good article on how to choose a law school. http://www.legalmatch.com/choose-the-right-law-school.html
Good luck on this decision and congrats on your acceptances!