I went to the Philadelphia IHOP late at night. Its convenient, a few blocks from the convention center in an area with several restaurants and bars and is open until 2am
My server showed me to a table right away. The tables were all clean and I had the place largely to myself, although several groups came in during my stay. It well lit, with windows looking out at the street.
My food was excellent. I had blueberry pancakes and sausage, cooked just right, with hash browns.
The prices were excellent, especially for a downtown area. I highly recommend it if your hotel doesn't serve breakfast, or if you want a family friendly meal downtown.