Both are great, but nothing beats detroit style.
Not sure I have a preference but I have had great NY pizza in lots of places including locally. The only ones that seem to get deep dish right is a few places in Chicago. I assume that means one is harder than the other to do?
I've come to lean toward square pies, like Detroit and Roman. Love the crispy char on the edges of a good Detroit-style pizza.
There is no bad pizza. I like them all, outside of the frozen cardboard pizzas, and even those can suffice in a pinch.
I'm a firm disciple of Portnoy although I've been trying a few of his higher rated places and having some disagreements. Went to one of his 8.9 places tonight but thought it was a 8.1. While his 8.2 rated place, rates a firm 9.0 for me. Thin and crisp for me.
If the only Chicago pizza you try is deep dish, you're missing out.
Regular crust, cut square instead of pie style, is what most non-tourists eat regularly.
5 stars!