Bari Pizza in Santa Ana (right near Tustin) - https://www.yelp.com/biz/bari-pasta-and-pizza-santa-ana
Fantastic New York-style pizza, good value. It's in a sketchy shopping center, but they deliver, so it's all good.
Angelina’s for authentic Neapolitan, Bari in Santa Ana for a big NY-style thin crust. These places know how to make a great dough, and they use top notch ingredients for everything. Order well-done if you need that crunch.