Yeah, that can be a hard choice (although I’m proud of the program for being able to make it such a hard choice).
There are a lot of factors to consider, and I imagine you’ve thought about a lot of those already. Grad school opportunities, location, potential research mentors, cost of living, etc.
Remember to also consider how well you can see yourself fitting at Northeastern. Do you like where Northeastern is in Boston? Are you okay with its personality (ex. President Aoun makes shitloads of money, but works hard to earn it – talking with students, writing up huge reports that he sends the student body. School is not really well established, but is rising quickly and building lots of new buildings/hiring new faculty. Student body is very large, but for the most part less partying/sports than most traditional universities, etc etc).
No one can make the decision for you, but hopefully that’s a good start. Good luck! And feel free to shoot me any questions.