First of all Carlos and Victoria could not be better hosts. They were very communicative and responsive, and I appreciated that.
The apartment was clean and basic in the heart of Madrid about a 10 min walk from Sol.
While my experience was not a bad one, I am not sure I would stay here again. The apartment building was very loud. I could hear the downstairs neighbors banging on walls and slamming doors at all hours of the day and night. It is on a street close to several hostels and the street noise was constantly loud and drunk conversations late at night.
The neighborhood itself is fine during the day, but as a single female I was not comfortable venturing out after dark alone. I travel all around the world solo and have a pretty good instinct about when and when not to walk alone.
I have stayed in several spaces in Madrid for similar pricing that were quaint and cute and better neighborhoods.
Overall clean, basic, good hosts, but I wouldn't repeat my visit.