(I deleted your other thread; it had no replies, and duplicated this one.)
Generally, I say “follow the money.” However, your situation is different because you are doing a special program; you will only be spending one year at JHU’s Bologna campus and will get an MA from there. I don’t know exactly how much JHU’s tuition is, but I’m betting that it’s around $40K and if you have to borrow for living expenses, that’s probably an extra $20K. So that’s $60K in debt for one year. I don’t think that’s too bad, especially since I think master’s degree holders in IR can expect to make around that much in their early career. That is assuming that you don’t have mega-debt from undergrad or from your current MA program, though. I think an MA from SAIS might open a lot of doors, too.
The UD program is simply an exchange program, so you don’t get an extra MA. However, you DO get the study abroad/exchange experience, which might be what you’re really going for. Besides, it’s free to you.
So I suppose it really depends on what’s most important to you. Do you want the MA from SAIS to open some doors in IR? Or do you want to experience a year-long study abroad in Denver?