Quoted from gweempose:

We order deep dish from Lou's at least once a month.
Lou's is awesome, but if you're trying to feed a lot of people, it's not very cost effective. Their deep dish is damn expensive. You're probably better off going with thin crust for a group that size. Plus, thin crust is just easier to eat in a casual setting. D'Agostino's has great thin crust pizza, and they are right down the street from the Westin.