I rented this flat for 2 weeks in October and I can only confirm the previews good reviews! The location is excellent, 1 minute from subway, buses etc. so it was very easy to move around the city. Shops and supermarkets are also very close and the lovely Palermo Viejo is only a 5 min. walk away.
Mauricio is an excellent host! I arrived very early in the morning and he was already there waiting for me, he gave me all possible explanations about the apartment and also maps and a guide about Buenos Aires. He also gave me some tips about other cities like Colonia and Iguazu since I also wanted to visit them. The apartment was extremely clean and tidy and I felt really at ease. Mauricio is extremely kind, since I didn't bring a hair dryer he bought one immediately!
Unfortunately we didn't manage to see each other a lot because we were both very busy but he wrote me almost every day on whatsapp to be sure I was feeling comfortable in the flat.
I would recommend Mauricio and his apartment for sure!