Cheesesteak fans look no further! Like the name implies, that's pretty much all these guys do, and they do it very, very well. Just to get it out of the way early: They use cheese sauce. I like my cheesesteak either way, but I understand there's some bad blood between the Sliced Provolone and Cheese Sauce camps.
If you're okay with the cheese issue, this is a place you need to check out. I'm going to assume you're familiar with the standard cheesesteak formula, but where these guys really stand out are their variations. The Seoul Man (Korean BBQ cheesesteak) and the Lone Star (I might be getting the name wrong, but it's the BBQ/bacon one) are phenomenal. The home fries, coleslaw, and potato salad are also winners.
Totally unpretentious and incredibly tasty. I've never been to Philly so I can't speak to the official authenticity, but these are more than good enough for me.