I am assuming we are leaving out the local mom and pop joints - which I generally prefer over any chain joint.
I try to avoid all the major pizza chains, not only because their ingredients are so heavily processed, but also because of some of the things their owners have gone on record stating regarding minimum wage and health coverage for their employees. The owner of Papa Johns for example lives in a castle, literally, and he was sulking about having to pay for healthcare for his employees and threatening to raise the prices of his pizzas - as if that is some sort of threat to the average consumer. It's pure greed and it turns me away from being a customer of theirs. Pizza Hut also got flack for firing a manager who wanted to give his employees the day off for a major holiday recently (I can't recall if it was Thanksgiving or Christmas). I mean, really? I'm sure the CEO's of those companies took the day of and enjoyed it with their families, but they can't afford the same consideration and respect to their employees?
There was once a chain called Pizza Pan in my area that would give you two extra pizza's when you bought one (store pick up) or buy one get one free all the time for delivery. Granted, their "one" pizza cost like $17, but it was kind of funny walking out with like three 14" pizza's just for myself, lol. The other catch with them was they were very very light with their toppings. If you got pepperoni, there were maybe like 8 slices on the whole pizza.