Secret..its in the water ! Article includes some interesting viewpoints from Mario Batali :

"New York has a grand tradition of pizza making and holds it dear," Batali says. Which means institutions like Arturo’s have been using the same equipment for decades. "An oven captures the gestalt of beautifully cooked pizza. And it imparts that."

http://www.wired.com/culture/lifestyle/magazine/16-05/ps_pizzasci