Well, obviously there is your subject of choice: one of the might be better than the other, even if the other is in some sense better overall.
Anyway, from what I can tell, Harvard would be better. [You should also take a glance at, say, the Philosophical Gourmet reports since there is overlap in theory with work done in pol philosophy].
This is also a very informative source of information:
http://www.blogger.com/comment.g?blogID ... 6346011299
It's a pretty wide-ranging affiar about departments in general; some rumors here, some rumors there, discussions about canon, etc, but also a good amount of discussion about which departments are best. I believe Harvard was granted superior placement over Yale in part thanks to the size of the faculty.