I would probably do Charlotte also, although I think that with either one, if your outgoing flight is late at all, you could very well miss the connection. Before you actually book it, you might want to check to see if there are later flights to get you home, in case you miss the connection. If, for example, there is a later flight from Charlotte one that gets you home that night, and no later flight from Philly (or vice versa), I would probably book the connection that gives you an option to get home that night if you miss the connection.