I usually find argentinean meat too much cooked. Try asking for "rare" or, in portuguese, "Eu quero a carne ainda mugindo" (I want the beef while still mooing).

And take in account how the meat is cooked: it is more difficult to cook the meat using a contact grill. At some places the cook keeps pressing the meat against the grill to accelerate the cooking process. This easily results in a drier, overcooked meat. On a contact grill, the less handled the better the meat: you should turn it only once, and never press it. Heat air dry cooking, as the churrascarias do, is much more forgiving to the meat.