The good part about PHL is you can walk airside from one end to the other so you can try a couple. The BA lounge is by part the best and opens at 3pm. The dragons can be quite aggressive if not on a BA flight so have your card ready. The new AA lounge is comfortable but in a windowless basement on A pier. There is an old lounge, used to be called the envoy lounge, in A pier on the way to the international gates up an escalator. Better views but they hand out the drink chits so be prepared to ration.