I think this is a question that turns more on one's definition of 'good' pizza than anything else. I found it, when I could eat gluten, to be good like airport cafe or mall food court fare and nothing more
we actually have a freestanding sbarro in chicago, way out on the west side in a residential neighborhood where you would never see it unless you live near it. i honestly like their calzones in the same way i like taco bell