Are you looking to go to Buenos Aires or other parts of the country? We just returned from BA. If I were to go again, I would only spend maybe 2 nights in BA. Slurge for a nice hotel in Recoleta. We went to a "so so" tango show. I would spend more and go to a better one if you really want to do this. My suggestion is to eat somewhere else and just see the show. The food is just ok and much better elsewhere! Gardener was my favorite place to eat!! We also went to an estancia to see the Gaucho show. They didn't have one which was disapointing and not as discribed. However, it was a nice day and good food. Would book directly with an estancia to make sure you get what you pay for though. We went to El Calafate and stayed at Los Sauces! It was my favorite part of our 12 day trip! (outside of the wedding we were there for) If we had been there during a more "in season" time, we would have done more. We were only able to take a boat tour of some glaciers and do the mini trekking which was amazing!
If we get the opportunity to go again, we will go north to the Falls, Salta and Mendoza.
I did find it very frustrating to communicate there and my husband speaks pretty good spanish.
I would not rent a car in BA but you could if you go outside of the city.