One caveat to UPenn is its Pennsylvania location - the PA malpractice situation is dismal. Thomas Bader was quoted a couple of years ago as saying that the majority of OB/GYN grads from Hospital of University of Pennsylvania have at least one malpractice lawsuit pending against them when they graduate. PA's crisis makes staying in PA after graduation difficult to imagine, and prior or pending suits, even if frivolous, can be a problem when trying to get coverage in a different state.
(Please note, I'm not criticizing the program, just the location)