Hi Nick!
I'm not sure if I have much advice for you but I'm interested in following this thread as I was also recently admitted to the NU Masters program. I'm currently contemplating the financial implications vs. the potential benefit from the experience. From what I can understand, it will be a difficult process to gain acceptance to NU's PhD, and if you were to take your Master's elsewhere the credits may not even be recognized to give you time off your PhD.
Looks like UHart seems to be your best bet at this point, but I'm curious as to what others have to say..
Good luck!