I like La Choza, and would recommend it to someone wanting traditional Parilla.
But I would choose La Carniceria over it. Also I like the downtown funk of Parilla Pena.
I often send first time visitors to Rodi Bar- they are open all day, serve a respectable Lomo, but also great pasta, salads, pastel de papas, and a full menu of classic Argentinian food, not expensive, and a real authentic experience.
Not Argentinian, but I go back again and again to Gran Dabang.