If you’re a oneworld emerald member flying internationally or flying British Airways first class, the only “true” first class oneworld lounge in the Philadelphia airport is the British Airways lounge, which has a dedicated first class side. All of the other oneworld lounges are AA Admirals Clubs, which are open to domestic passengers (the previous US Airways Envoy lounge that was reserved for international passengers is now a generic Admirals Club).
That being said, if you have AA frequent flyer status, the only time you’re supposed to have access to the BA lounge is when you’re flying internationally. There are reports of people being turned away because of overcrowding (even when it’s not very crowded), but I’ve never had any issues in the couple of times that I’ve tried.
To the left is the first class side; to the right is the business class side. The lounge itself is pretty small and has somewhat limited seating, so I can understand why they might turn people away.
There is a “First Dining” section of the lounge, but that’s only open when the British Airways flight with first class is departing, and I believe only people who are actually flying first class on BA are allowed in.
The food options at this lounge when the dining area isn’t open are okay for a U.S. lounge but really sad for an international first class lounge. There are cheeses, hummus, sandwiches, fruits, crudités, chips/crisps, and candies. I’ve definitely been in the lounge and overheard passengers berating the lounge staff for the meager options (which honestly is not helpful because the lounge staff can’t do anything about the fact that the food options aren’t great). The food selection is slightly better than the food selection in the Admirals Clubs, but that might change when they make a flagship lounge in PHL.
The wifi in the lounge works fine, but the lounge is somewhat lacking in electrical outlets. If you’re in PHL, you don’t have any better lounge options, so you might as well come here if you have access. But don’t be too disappointed if the lounge agent doesn’t let you in since you’re really not missing much.