I had a very good stay and Andres's and Mercedes's place. Mercedes was always very communicative and responsive both before and during my stay, making sure that everything was going according to plan.
Check in was with the super friendly Diego (the building caretaker) and the apartment was as described in the posting. Functional kitchen, practical living and dining area, and a very comfortable bed and pillows.
The apartment has a small but very nice balcony (high floor) with a very open view of the city and the Rio de la Plata in the background.
I am a bit biased about the area as I lived there for three years and never stopped liking it. It's a proper Buenos Aires neighbourhood - a very residential place but at the same time with plenty of options for bars, restaurants and shopping expeditions. Local transportation is handy with plenty of buses, the metro station nearby and of course the affordable taxis.