Gustavo has a very nice and cozy apartment, very well located between Recoleta and Palermo. He is responsive and very kind and did all he could to make us feeling at home. I definitely would stay at his apartment again.
The only thing one must be aware is that the bedroom is located in a mezanino, so you have to climb some steps to get there and it may be a problem for elder people and/or to people with difficulties when moving around.
Despite that, the apartment is quite nice.