I had very good time at Martin's apartment. Everything was perfect. Apartment was very clean and comfortable and I could not find a better host. Beyond the fact that Martin is an expert on Argentina culture, history he also knows a lot of things to do in Buenos Aires and gave me valuable tips.
If you are looking to a place to stay in Buenos Aires, I strongly recommend Martin's apartment. Neighborhood is also the best in town, with lots of good restaurants, active nightlife and easy access to public transportation.