Most people I know will recommend rotating at one of the Mercy sites - Philadephia (aka "miz" as it used to be called Misercordia, which is in West Philly) or Fitzgerald (in Delaware County). Heard good things about rotating at St. Joe's Hospital. As for Hahnemann, it's where all the main faculty work, so if you want to try and get in with them, go for it. But, a lot of the faculty (not all) could care less about the students and have them present to the PGY-3s who then present to the attending. At the other sites, you will get one-on-one interaction with attendings, but a lot of them are newer and less known in the greater EM community.