We love Marcelo's in Puerto Madero, on Alicia Moreau de Justo. In same ownership as Piegari on Posadas, Recova, but more modern feel, great place to take clients. Also on Posadas is Mirasol, great steaks and imho the best empanadas in town. Very traditional, little fancier than most parillas, seems like wait staff have been there for centuries. We're Cabrera regulars and I recommend the food, but both locations are always crowded, we've often waited more than an hour to be seated. Miranda also great.