503 is an upper box that sits perched just above the North endzone. There were no seats to our immediate left which was kind of nice. Not the most ideal place to sit at the Superdome but the view was fine and the 500s offer a far superior view than the 600s and have fewer seats comprising each section.
You will share the same restrooms and concessions with the 600 level patrons if your seats are in the 500s, FYI.