I live in Philly, and have been here a couple of times. The food is pretty good - better than I expected given the touristy nature of the place. The service, as many others have mentioned, was poor. One of the meals was brought out cold and when we sent it back to be heated up, we never saw it again. The waiter was rude and indifferent.
A recomendation I would make is to go here for desert or drinks. There is a lounge with period furniture and a harpstichord. We were there on a saturday - I'm not sure if they play every night. In other parts of the restaurant, there were other musicians. The beer (which is brewed especially for City Tavern) is excellent, although a little pricy ($6.50 a pint). The desert my wife had (chocolate mousse cake) was very good as well.
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