Since moving to DC a year and a half ago, I've been to 2Amy's about ten times. I think that's a sufficient sample size from which I can draw some solid conclusions. The pizza is legitimately Neapolitan, and the story of their method/authenticity is printed on the back of the menu. The crust is the best pizza crust I've ever tasted. This is a result of their ingredients and wood-fire ovens. The cheese and toppings are delicious as well, but not to the same mind-blowing extent as the crust. A pizza will generally cost about $13, and if you are hungry you will eat the whole thing. If you're really hungry you might want a bit more food. If you aren't that hungry and have a light eating companion, you can get away with splitting one. My wife and I usually order a prosciutto and mushroom combo, but everything is good. The stuffed pizzas are also very good, and massive (the pesto one is surprisingly good). The service is fine, and once you get a table you usually get your food pretty quickly. However, it's always busy, and if the weather is nice you can generally expect a small wait.
I go with a four instead of a five star rating because I'm a bigger fan of higher volume pizza consumption. If they cut two bucks off the price of all the pizzas, it would be a 5! All in all I don't see a reason you shouldn't give 2Amy's a try.