You know, you can order them without onions. That's what I do.

Gregoshi hit most of the main points, but I will add that there's a certain type of bread that is required to complete the steak. They are known as Amaroso rolls (from the Amaroso Baking Compant). Geno's uses them; Pat's doesn't (one of the reasons why I prefer Geno's).

Also, a lot of the people who eat at those two places are labelled tourists because they only go where it's famous and not where it's actually good. My favorite cheesesteak place is Tony Luke's, which is a short way's off from P&G.