4 years ago, my wife and I did our own "best pizza in Pittsburgh". We tried pizza from 12 different places in Pittsburgh. Fiori's came in to this competition as our favorite spot and after trying 11 other spots, Fioris's still is #1.
Nothing in this world beats their double crust pepperoni pizza with a side of cold cheese. Keeping it simple. I now don't eat dairy but every couple months, I get crazy and get some pizza from Fioris.