30th Street is pretty decent. I rented from them again last weekend on another trip to Philly. Got upgraded to a 2014 Chevy Traverse LTZ with 2000 miles on it. I usually come into Philly by train anyway so this setup is just perfect.
Even still...you can easily hop on the commuter train from the airport and get off at 30th Street. The fare is at most $10...if you're saving $90 - $100 the extra 20 minute ride into the city by train is worth it.