The apartment is in Recoleta, a nice middle-class neighborhood, and the address on the Avenue Santa Fe is very convenient. It is easy to walk to many places such as Teatro Colon or Recoleta Cemetery (resting place of Eva Peron). It is also a short taxi/Uber ride to other important neighborhoods such as Palermo or the city center.
The host Lilian is a very warm person who went out of her way to make sure that I was comfortable. She gave me a great deal of helpful advice about buying a local SIM card, about changing dollars for pesos, etc.
I enjoyed my stay very much and if I return to BA I will stay with Lilian/Maria!