Any pizzaria outside Chicagoland that tries to make deep dish is going to screw it up. Guaranteed.
As a native Chicagoan, even one who does prefer New York pizza, I have to say this statement is entirely correct. The best example would be Uno's. The national chain is absolutely horrible, and their pizza bears no resemblance to the sublime creations served at the original location. A pizza from the real Uno's, with their homemade sausage, is a local delicacy. No, you can't pick it up, fold it in half and stuff it into your mouth like a NYC slice. But it's still great. The chain doesn't even come close to duplicating the taste and texture of the real thing.
Nick