Georgetown takes TONS of transfers (about 80 this year); check Penn's website, they usually say how many transfers they take. Georgetown is a tough school to transfer into, unless you're well aware of -- and ready to tolerate -- the Georgetown snobbery (think DC agendas + East Coast attitude + privileged law students ... it's not pretty). I'd strongly consider it if I was interested in politics, international law, or tax. Georgetown also takes early decision transfer applicants after the first semester grades are in, I don't know of any other school that does that. This makes it really easy to transfer if you get great grades after your first semester and end up being a fluke and doing worse your second (happened to most of the people I knew with 3.8+ GPAs after the 1st sem).
Something important to think about (and I think most potential transfers don't) is the size of the class. Georgetown's classes are like 550+ students each, so it can be really hard for transfers to blend in and get to know a lot of their colleagues (then again, it's hard for 1Ls, as well). If you go to a school with a smaller class (Yale, Chicago, not sure about Penn) you're going to get to know people within a semester and (if you're lucky) fit right in as if you started your first year. Transfers often feel isolated at their school, so if significant social interaction is important to you, take that into consideration.