I don't think anyone's mentioned yet, but another perk of some of the more specialty-oriented schools is that they may have breaks or lulls planned into the schedule when potential applicants have downtime to study for boards (old) and CBSE/ADAT, verses GP-oriented schools that will not give you such a convenience and you have to pile on studying for the CBSE/ADAT on top of everything else.
Just to comment on the rank/unranked, yes you will stand out more as a ranked applicant if you are highly ranked (ie top 10) rather than one who is unranked. However, if you feel you would NOT be ranked highly, then going to a P/F school would be advantageous. Just personally, I would like a system like at Columbia where they rank in thirds. Takes some stress off of OHGODIHAVETOBEFIRST, yet you can still shine by being in the top third (or ten, whatever).