Elisa and Carlos are wonderful hosts, always available to help and very efficient. The apartment is as you see it in the pictures, fully equipped, functional, clean and in a very good location and, what seemed to me, in a safe neighborhood. If you want to visit other areas of Buenos Aires, the nearest subte (metro) stop is literally 5 min walk from the apartment, line D going to Plaza de Mayo, etc.
If you go there my advice is to pay a visit to the very close La Peña del Colorado and attend a "Guitarreada en las mesas" after midnight. You can listen to (and sing) folk music played by the guests!