Our experience at Andrea's apartment at Humahuaca street was great.
The apartment was very cozy and comfortable, we were 4 people staying there, my two sons, my wife and I. Very luminous and roomy for a one bedroom apartment and fully equipped. All the appliances in the kitchen were new, big glass table in the dinning/living room, for at least 7 people, TV and computer. Big closet in bedroom. Having an A/C in each room was a huge thing in the middle of the hottest summer ever in Buenos Aires, temperature reached 40 C/104 F, however the last few days the weather was really nice, temp lowered to 28C/82F, and we didn't have to turn them on as we opened sliding doors from the balcony and the room letting nice fresh are was going through the whole apartment.
The apartment and the building in general was very clean. The location is perfect, it is located right in the middle of the city, close to many different places of interest and neighborhoods you may want to visit: Belgrano, Palermo Soho, Palermo, 20 minutes to downtown, etc., and most importantly you have public transportation to go almost everywhere (Metro station in the same block.)
Andrea and Raul her husband were very nice and kind with us. Andrea provided everything we needed from the time we checked in, she took care immediately of an issue with the A/C (the only issue we had) and most importantly they helped us a lot when the major power outage took part in different areas of Buenos Aires City, she was always on top of this matter and tried to get us another place to stay temporarily while the outage was going on, until we got power back the next day.
Also few relatives of Andrea's husband live in the same building, which makes this place very safe and you can rely on them if anything happens.
I would definitely rent this apartment again next time I visit Buenos Aires.