I am a graduate of the IED MA program and was recently accepted to the Ph.D. program. TC is an expensive school and its worth really depends on what your long term ambitions are. I think it is great for a career in Academia (I was suprisingly accepted to 4 Ph.D. programs from top-notch schools, I believe primarily due to my TC masters degree) and if you are trying to move into a career in the non-governmental sector, TC will provide you with a great amount of internship opportunities.
From my experience the IED program is strong and there are some top-notch professors. The whole diploma-mill talk is really department-dependent. I don't feel the IED program falls in this category. I am not sure, however, if TC is worth 40k/year asking price.