Hi Dante, I was also recently accepted into the program. My impression is that the Columbia graduate Poli Sci dept. overall is a bit crowded and impersonal - not a lot of mentoring unless you specifically seek it out ("Graduate factory " was the exact phrase I heard). And the price tag, esp. with no financial aid, is obviously very high. On the other hand, I'm not aware of any other school offering an MA that is on Columbia's level, especially if you want to stay in the city. NYU has an even worse reputation as far as admitting a ton of unfunded MA students and giving them little in the way of support or interaction.
Feel free to send me a personal message - it would be great to be in touch with a future classmate!