Very late reply here.
I got off NYU's waitlist after I had accepted Northwestern already. Even before I got into NYU I accepted the fact that I would be happy at Northwestern's program over NYU's.
In terms of academics and faculty, NYU seems to be top tier. But the program design at Northwestern seems to make up for the lack of a specialized *Center for Data Science* that NYU has. Northwestern has a smaller cohort, and seems to be more professionally-focused, whereas NYU seems a bit more academic. Also, financially, being in Chicago for 1.5 years and having the opportunity to make money in a summer internship works out better than being in NYC for 2 years.
If I hadn't gotten into Northwestern, I would have been very happy to accept NYU as a close second choice. Good luck with your decision!