Maybe I just have plebian taste but I don't notice any difference between Domino's and Pizza Pizza quality. And I'm never in a position where I eat that shit side by side in comparison. And if I ever notice a quality difference with "higher-end" chains like Pizza Nova, Pizzaville, Papa John's, etc. it is a very marginal difference to justify such a huge price differential.
Some of those Delissio thin & crispy frozen pizzas are downright nasty though. That is when I really had a "you get what you paid for" moment.