SORRENTO is one of the best restaurants in Buenos Aires.  Typical Argentinian food, excellent service, top quality.  The pastas are delicious, home-made, and so is the rest of the menu.  The atmosphere reminds that of the old classy restaurants, elegant, sober, they know their "metier".  You may want to check their website:   http://www.sorrentorestaurant.com.ar/