My stay with Grace was fantastic from beginning to end. She arranged for a driver to pick me up from the airport, and I was also able to get him to take me back at the end, which saved me a lot of fuss and bother. When I arrived she greeted me warmly, and had lots of great tips for making the most of my stay -- the dinner place she recommended was a true local experience, and I would never have known about it otherwise!
The room itself was exactly as advertised, and the single bed was very comfortable. The balcony looks out into the neighbourhood, and it's true that Buenos Aires doesn't sleep! I didn't have any trouble though, and I enjoyed being able to open the door and stand on the balcony in the cool evenings.
The location is fantastic -- the neighbourhood is lovely, and it's possible to get to most things you'd want to visit in BA by bus or by (long-ish) walk. The famous Recoleta cemetary is just a few steps away, so even if you don't want to go very far you can see amazing things.
Overall it was a great spot, and I'm glad I got to stay there!