There are different bread options, there are many different cheeses that work well in this delicacy, and too many other options to list here.
For the record, I like mine on sourdough bread, using American cheese with some mayo and grilled slightly crisped and sliced into two triangles.
Where the locals go: the 22 best spots for cheesesteaks in Philadelphia as picked by people who live and eat in Philly (Pat's and Geno's are not on this list!).