Emma has some of if not the best pizza in Rome. To my knowledge, no one else makes pizza with black-truffle mortadella.
I don’t know that Rome does Neapolitan-style as well as LA. In Rome you want to eat Roman pizza, which comes in two types: a taglio aka rustica, for lunch or a snack by the piece, often sold by weight (Bonci is the king of that styles) to take away, or very thin round individual pies, at sit-down pizzerie many of which are open only for dinner. Emma’s pies are that style and they’re open for lunch.
There’s also the kind of “pizza” that they sell at Forno Campo de’ Fiori and Antico Forno Roscioli, which is sort of closer to focaccia, six-foot-long breads sold by the slice or weight. At the latter they also make sandwiches with them.