Alexandra is such a wonderful host! I lived in her house for two months and I didn't have one bad experience there. She is very friendly and quick to offer advice and invite you along on a bike ride, a dog walk, to the park, or to concerts or cultural events. She's very open and welcoming, while also being clear about the house rules so that things stay organized and everyone is on the same page.
The house is large and comfortable. There are up to five other people living there at a time, from different countries around the world, and everyone who was there while I lived there was very friendly. That said, if you're not used to living semi-communally, it might take a bit to get used to living with that many other people in such close quarters--the individual rooms are a good size, as are the kitchen, living room, and balcony, but they are always in use by someone. You will rarely have the house to yourself. The house gets beautiful sunlight, a nice breeze, and there are lots of plants, as well as dogs and cats, so it's a lively place.
It's also in a good location. It's within close walking distance to the metro, which is also right next to a beautiful public sports park. There are smaller parks, minimarkets, cafes, bars, and restaurants all nearby, and they're part of the quiet residential areas of the neighborhoods of Laureles and Estadio. There are also the main streets of San Juan and the 70 that are busier and full of entertainment, and the downtown is easily accessible as well, only about 20-25 minutes total of walking plus metro time.
Overall I loved my stay here--it is definitely a place to stay for a longer period of time, rather than just a few nights. I would stay there again in a second--it's a great neighborhood, great house, and great people.