drexeler, first of all, when you say "research", what exactly do you mean?
both Penn and Drexel are in west philly. Drexel goes out to about 34th st and Penn goes out to about 41st st. The bad parts of philly are either a lot more west, or a lot more north. There is virtually no "thug" crime anywhere on Drexel or Penn campus. Sure if you go to live off campus 10 blocks away from campus, you'd probably want to take extra precautions, but most people live in the general vicinity of Drexel, Penn, or Powelton Village, which is patrolled by drexel public safety, drexel police, philly police, penn police, penn public safety, university city ambassadors, etc. I don't know where you heard 30th street is a bad place. 30th street is across the street from drexel's campus, and very nice and 30th street station is packed with cops everywhere, postal police, amtrak police, septa police, philly police, etc.
you will see the occasional homeless guy or bum asking you for money just like all cities, but they don't do any harm, so don't let that scare you. i've never heard of that murder statistic on upenn's campus, and I can't remember any time in the past few years a student's ever been murdered.
sure you don't want to be drunk walking around alone at night in a bad neighborhood. i really can't think of anyone that's decided not to come to either drexel or penn because of so called "crime".
bottom line is see for yourself, come to drexel and look around for yourself, or rome the area at night, or better yet just ask some random students what do you think of the safety. i'm sure they'll give you more of an answer of how annoying public safety is for being on every single street corner at night or about their parties being busted than some story about a crime.
also, take a look at this article that just came out: Public Safety ranked 11th in nation - News