If I were you, I would seriously look at which school has the best faculty fit for you, even if it isn't the overall better ranked school. If your primary interest is institutions, I would say that GWU is your best choice. They have a really nice group of people, including Binder, Deering, Lawrence, and Maltzman.
As far as your two main choices are concerned, Maryland has Karol and Lee, but they seem to have a bigger behavior group (correct me I'm wrong--I'm not all that familiar). I'm not too familiar with Pitt, either. As far as behavior goes, Stony Brook is great. And outside of Thurber (who does really good work on congressional-presidential relations), American is much much stronger in behavior (with people like Lublin, Leighley, and Lawless).
