I'm a fan. I've only had good times happen in The O. It was the first stop when visiting Pittsburgh for schools with my father who was an alum (both of The O and the school).
I most recently tried the cheesesteak (needs more cheese), chili cheese dog (needed more chili), fries, and beer. The O is open late and never let's me down when I'm out and needing something at 1am. The fries are awesome, needless to say, given the previous reviews. I'm a ketchup kinda gal. So that's all I need. But to each his own, and while everyone I've been with loves the fries, it's interesting to see the different sauces people douse them with. My German exchange friend did mayonnaise while my roommate did Dijon mustard. Honorable mention to gravy.
This is college late night food at it's finest. If you're going to school in Pittsburgh, going to The O is a rite of passage.