Called for birthday reservations, and the only thing available was 9:30 pm (Saturday 6/12). Choose to sit at sidewalk tables, because inside the restaurant was broiling (our only complaint for the whole evening)
My S.O. had the onion soup (delicate), the mussels (delicious and spicy), and a fillet in mushroom sauce. I had steak tartare and the salmon. The guy next to us had the lamb chops (which he shared with us - he tried some of our food). Everything was exceptional, and the whole meal, (excepting our neighbor's lamb chops) but including two desserts and espressos was $83. The menu on first glance doesn't seem that exciting or innovative, but we were surprised - everything we had was flat-out wonderful. The other diners seemed pretty happy as well - the people leaving the next table as we arrived raved about the spinach salad (??!). Service was cheerful and knowledgeable.
Evidently, the mussels are a crowd favorite (they were good), but my steak tartare was absolutely astounding. Fortunately, we were able to communicate our enthusiasm to the chef, Ken Shapiro, who came out to talk to us (or maybe he was really shooing us off, since we were among the last there!) From what I read in the Inquirer and City Paper, he was with Le Bec Fin for a long time -- it shows in the cooking.
We're also fans of the Fayette Street Grill and Spring Mill Cafe, and can't believe our luck that an even better BYOB has opened within walking distance of our house.