I just returned from my first trip to Buenos Aires.
A majority of the time I was with friends who couldn't get enough of Cabana Las Lilas and Sotto Voce. I made several attempts and finally was able to try El Desnivel (difficult to know their operating hours), as that was given recommendations for a not so high end restaurant with good food. I went to a random parilla stand (one of many) lined along the Parque Mujeres area. I wanted to try the Choripán that people seem to rave about. Also found a supermarket (Jumbo) to buy some items to take home and a wine vendor (Tiempo de Vinos) for some decent Malbec to take back with me. I wanted to do some other things like take a cooking class and try some other places, but the Labor day/Sandwich Day (not food related) interfered with my plans.
The goal was to stick to eating foods I couldn't get at home. Only failed once when I got a hamburger at the hotel.
Anyway, I'm hoping to write up a report, or at least post some links and more detail on this page about the foods and such that I experienced on my trip.
Thanks to everyone for the advice and info posted on this thread.