We (my wife, a friend and myself) stayed at Horacio's apartment for a week.
Horacio is an amazing host. He's a kind and funny person and from the moment we arrived he went out of his way to make us feel at home at the apartment and in Buenos Aires. He took the time and helped us get oriented in the neighborhood, explaining in detail where the public transportation stations are, the supermarkets etc.
Throughout our visit Horacio was always available to answer any of our questions and respond to any requests we had.

The apartment itself was even nicer than in the pictures. It's clean, comfortable, well-equipped and spacious. We felt there was more than enough room for the 3 of us. The kitchen had everything we needed to cook proper meals, we had clean sheets and blankets for all the beds, hot water was always available and the bathroom was stocked with more than enough towels and soap bars.
The apartment has a nice little patio which is amazing for sun bathed breakfasts or evening drinks.
The weather was pretty warm while we were in Buenos and the apartment proved to have good natural air circulation (and there is of course the air conditioner for hotter days).

But above all its the location, location, location. The apartment is situated at exactly the right place, with Palermo Hollywood on one side and Palermo Soho on the other. We didn't have to walk more than a couple of minutes to get to any of the great spots Palermo has to offer. Buses to all directions run on the street below the apartment and the Palermo Subte station is a 5 minute walk. For grocery shopping there are two small supermarkets just around the corner and a huge one a 10 minute walk away.

We had an amazing time in Buenos Aires, and Horacio's apartment had a major role in making our experience so good.