We had a great stay at this apartment. Its in a great area of Buenos Aires - with all the bars and restaurants of San Telmo on your doorstep (as well as the Sunday market).
The apartment itself was lovely. We were only a couple so we were only using the main double bed (with was really big and comfy!). But there was also an extra shorter bed (probably not for an adult) and a foldup bed if there were more than two of you. Only thing to note if you're using the kitchen for cooking is that there isn't a sharp knife or a can opener. We had a pocket knife and didn't buy canned food so it wasn't a problem.
The amenities in the apartment building are also fantastic. There is a nice big pool with loungers, a jacuzzi, and a good gym. There was also a laundry room (you can access this by using the service elevator and going to floor EP) - you can buy tokens from the security guards at the front of the building for 25 pesos each.
Esteban was a great host as well - leaving us champagne and coffee pods, and also helping us out when we had difficulty accessing the pool/spa (for reference if the main door from reception is not open then there is another access pathway to the right of the door to the apartment, and the facilities are open 8am to 10pm).
We would definitely stay here again if we were back in Buenos Aires :)