Tough call. If it were not for the money, I would say MIT Sloan hands down. Sloan has a way bigger/better startup ecosystem than Booth.
I think it should go down to your personal finances, and think which school will be better for your startup.
MIT's resources in Entrepreneurship are limitless: The world renowned Martin Trust Center that throws money at any startup through its doors, MIT's Sandbox, Cross-MIT resources, MIT's 100k Competition, VCs parked right on campus that focus all of their funds on MIT startups - are all hard to turn down.
Perhaps by quantifying MIT's resources it will surpass Booth's 90k. Therefore it all depends on what Booth has to offer.
A big difference is that Booth has a Chinese wall separating it from the rest of UChicago, while MIT Sloan is integrated within MIT (part of the broader institution). For startups, the latter works better, you get to leverage all of MIT's resources and alumni.
Congrats on getting into two amazing schools! Best of luck in your decision!