Very dramatic image, but it would have helped to have some light in the city itself. It's also not emblematic of Philadelphia as it's similar to several photographs in this challenge.
In general, I like the composition, a classic postcard image. It looks like the sun just set, so the colors of the sky are nice. However, if someone sent me this postcard, my impression is that Philadelphia must be a ghost town. The buildings are dark, the bridge is dark. If the buildings in the skyline were lit up with office lights and the bridge had lights on, I would have a better (positive) impression of the picture and Philadelphia.