Great apartment, highly recommended! Central location, close to many restaurants and public transportation. Very safe as well. The building itself is small, with few apartments, and internally very quiet. Of course on the outside you have the city and you should expect some noise, as with any central, dense neighborhood.
The space is very well designed! Even though the apartment doesn't have a separate enclosed bedroom, the loft area keeps the sleeping area pretty private. Spacious living room. Good, functional furniture. Appliances worked well.
Everything was clean when we arrived. We stayed for a month, and the apartment was cleaned a couple of times during our stay, with changes of sheets and towels, which was a very welcome surprise for me (I hadn't realized that service was included).
Martín was always available and helpful--great host!
Next time we visit Argentina, I'll make sure to look into the availability of Martín's apartment.