I've never been to Philly unfortunately, it's one of the few big cities in the US I haven't been to.

However, I used to go to Ohio a lot and one time when we went to the Football Hall of Fame to see Montana and Lott (among others) inducted, we stayed in a town called New Philadelphia. Next to our hotel was an authentic Philly Cheesestake place owned by people from Philly who owned a bunch of carts that sell them in Philadelphia. I was 10 years old, I hate like half of it but it was soooo good. They even served it in those brown bags just like the carts where the greece goes halfway up the bag. In fact, I have a picture of the bag and sandwich somewhere in some photo album somewhere.

Tony Siragusa, the former Colt and Baltimore Raven, once ate 2 Philly Cheesesteaks like a half hour before a game (that was later canceled) on the first season of Hard Knocks. And they were big even for him.