I've worked in a Dominos and Pizza Hut.  Taste aside, Dominos do not use any frozen products (our only freezer was for icecream) but Pizza Hut freeze pretty much everything, including the dough.  Then a load of oil goes in the pan when it cooks.  The Hut I worked in was inside a supermarket so we used fresh veggies but I bet those come frozen at most places.
Taste wise, Dominos is better but still isn't great Pizza.  Make your own, it's easy.