I had to make the decision between HKS, SIPA, SAIS, Tufts, Georgetown SSP, and more. I chose Jackson after I visited.
The experience I have had so far may not be the same for everyone, but I'll share it anyway. I love the ability to chose my own concentration and the fact there's only 3 core classes (in addition to the language requirement). This semester I'm taking a Global Order Class with the former first Prosecutor of the International Criminal Court, a leadership seminar with General Stanley McChrystal, an SOM class on Global Catastrophes that brings in leaders in the field to talk each week, a Yale law course on human rights, and a French course.
I regularly attend small lunches with the senior fellows, current and former ambassadors, and other leaders. I know all the top schools likely bring leaders in, but at Yale I've gotten the opportunity to actually have conversations with these people, rather than just listen to a lecture.
Although the Jackson name is new, Yale had an IR MA program before, and we've met with numerous alums. I've emailed and had lunch with a few, and one even helped me prep for my internship interview at OHCHR. Also Yale has a database of all Yale alums and I've contacted a few who now work in fields that I'm interested in. One even set up a Skype session to answer my questions because she was out of the country.
If you got into the Jackson Institute, visit! If you can't make the admitted students program, let us know if you can visit another time or if you just want to chat with some current students.