First off HUGE Congrats! If I were in your shoes I would choose according to the industry/region in which I'm planning to work. Both New York and Chicago are well-known financial hubs. Chicago seems to be a fairly economical choice if you haven't received any scholarship from Tandon, and Gatech too is pretty good economically. Well, in that regard purely, Stony Brook QF is the way to go at (45k) tuition. 😛😛
Secondly, Just going by rankings, the University of Chicago itself is among the top US universities (US News) rankings and so is their FinMath program specifically (on Quantnet). NYU closely follows UChicago in university rankings and leads marginally in program rankings. Gatech lags behind in either.
But keeping ranking metrics aside (however lucrative they may seem to adhere to), I feel the Chicago offer is the one to go for. They do seem to update their curriculum as per industry standards/demands. (got this info. talking to alumni)
Could you tell me how long you have to accept either of the three offers (NYU, Chicago, Gatech)? I'm still waiting for both Chicago and Gatech decisions.