Stayed at Gonzalo's flat for around ten days as a couple. It's in a fantastic location and very spacious, easy to get around the city and enjoy the surrounding neighborhood, which is far less touristy than other parts of the city. The AC works well, the shower has good water pressure, the bedroom has blackout shades, and the kitchen is well equipped. In general, this feels like a real apartment, rather than the cookie-cutter IKEA setups designed exclusively for Airbnb.
Gonzalo himself was a wonderful host. We had an issue with the bed which he fixed the next day. We locked ourselves outside the apartment and he rushed back to let us in despite being out of town for the evening. It's clear he cares a good deal for the apartment and for his guests. Happy to recommend him and his apartment very strongly.