I'm in the same boat you are. I luckily received a $12K scholarship from the Korbel School, but that merely makes it roughly the same price as SIS.
Given the fact that I applied to the US FP program at SIS and that my intention is to get into a career in Int'l Relations, I am likely going to choose SIS.
I guess it would depend on your program. For instance, I know that Denver has a tremendous Human Rights program and if that were my interest, I would chose them.