Quaker State is a Shell Oil Products, USA (SOPUS) brand, just like Pennzoil. They all use similar (though probably not identical) additive packs. So essentially, the answer to the question "what's the difference between QS and PZ?" Is "one has a yellow bottle; the other, green."
Both use oil sourced from "wherever's cheaper"; note it says "Pennsylvania GRADE oil," which in this case, means roughly what Ford's "military GRADE aluminum" means. AFAIK, the only oil co. using actual Keystone State Lube is Brad/Penn (originally headquartered in...Bradford, PA.)