The Chicago beef sandwich is awesome!.
Never been to Chicago, so I don't know if it's authentic Chicago grub. All I know is the Chicago beef sandwich is incredibly good. The sandwich is huge with ton of meat that is perfectly seasoned with Italian spices. You also get a big pile of seasoned, fresh cut skin on fries that are fried to perfection.
I've had a dozen of these now and each one is as good as the last.
I also have tried the catfish, which I had in a sandwich version. Yummy!
The only thing I don't like is the location. To many undesirable people milling around outside.