I am highly considering SIPA as well and the high costs are also a factor weighing on my mind. I've been out of school for a few years and I knew that at some point I would be returning to graduate school and saved accordingly for some of my living expenses, emergencies, etc. I keep hearing the "cash cow" mentality repeated on this forum regarding SIPA -- but as the previous poster mentioned -- most terminal masters, MBA's, etc. are considered pure cash flows for the university. Indeed, if you are following the market/news, even going to law school -- even the top 14 schools -- these days is a huge risk as well and does not justify the return on investment for many graduates. For many of these programs, all the university has to do is provide a desk (and not even that). There has actually been (not surprisingly) blowback regarding the Harvard Kennedy School in the past few days given the scandal surrounding Bo Guagua (a graduate student there) and his parents in China.
At the end of the day, going to graduate school is an investment and you have to weigh all the costs of attending, including lost salary of 2 years. I think it is important that you have a mapped out plan of what you want to get out of your program and what you want to do after school. The benefits of many of these policy programs, as opposed to an MBA is you can specialize and stand out instead of being a generalist. One of the reasons I like SIPA is that they have an incredibly diverse array of courses and the opportunity to take very specialized classes as well as get a solid grounding in economics/management and quantitiative areas. They are not going to hold your hand step-by-step but the resources and the networks are there, just like in real life. I am also attracted to the fact that there are many international students. We live in a global society and although I may not remember certain facts from graduate school in ten years from now, having friends/contacts in different parts of the world will be useful professionally. I met a few prospective students at the admitted students day, and everyone I talked to had a really interesting background/work experience and specific interests for their studies. Having been in the work force for a while this is incredibly important to me.
I hope to make my decision in the next few days -- good luck to everyone as well!
Cosmic Grad, I agree with you on the line "They are not going to hold your hand step-by-step but the resources and the networks are there, just like in real life. I am also attracted to the fact that there are many international students". I was having trouble choosing betwen SAIS and SIPA. In the end I pick SIPA, accept their offer and immediately decline the other schools. And I feel great and relieved I made that choice, now I just cant wait to start the fall semester,esp the fact that SIPA will open a new center "center of global economic governance" which is my favorite subject.
As to the size, SIPA is a very large program. In fact, it was the largest program I applied to and it was a concern of mine. But in order to make the right decision, you need to be honest with yourself about what kind of program you need. Because of SIPA's size, it has an enormous amount of course offerings, in almost every policy subject - domestic and international. There won't be a topic that isn't covered through coursework or programming. This also means that SIPA has networks for capstones and projects that extend into every program area. Additionally, we can take courses at all of the other top graduate programs, the Business school, the Law school, the School of Social Work, Teachers College, and the Public Health school. On the other hand, I must expect classroom sizes from around 15 to 60 students. While teachers regularly meet with students, they aren't always available for one or one attention or guidance through every step of your academic experience. So in line with what Cosmic Grad says, Columbia is like New York City, you must be ready to seek out what you need and can't be timid about accessing help and support. But everything is there!
To add to Erry and CosmicGrad:
Most programs do not seem to offer international focus in the curriculum and I also feel that SIPA gives you the opportunity to decide and work towards a specific goal by picking a concentration, so for two years you know where you're going and your energies are channelised in just that subject/sector be it Security, Social sector, Economics, finance etc. Also one great advantage of SIPA is the mix-match with other schools. Although other schools may also provide this possibility, I feel Columbia has a more global appeal. I know for a fact that Columbia is a very well known name with donor agencies, government etc in South Asia (having worked in this sector.) I also feel that SIPA's international student body is definitely a pull-factor because in, say, subjects like development economics, perspectives (live ones) from other countries/regions makes discussion/presentations and learning a lot more satisfying, complete and they're embedded better. And like Erry and Cosmic Grad said in a globalised environment it makes sense to work towards networks across the world. In the end, as an international student, perhaps, my choice about the city matters and in this case NYC, for me, I believe, is the best choice and after talking to some other international students from SIPA, I feel NYC is a top pull-factor among others.
PS: the faculty is amazing, although I have not attended the students day, but I saw all the videos for both this year as well as last two years and they've across as motivated, experienced people who're slightly on the idealistic side, but I guess that's one huge positive on their side. As far as getting individual attention from professors is concerned, I think, THAT is something which anyway grad students would have to make efforts towards, no matter where you are.
Having said this, many congratulations to everybody for your schools ! This thread has been amazing!

Cheers!