We had a great stay - there were ten of us, for a fun weekend in Madrid as friends. The flat fitted us fine, 2 per room (one room is a maisonette style on top of another room). Loved the area, very mixed, residential, lots of places to go in walking distance. It was easy to ask the hosts local reps questions via whats app and get quick answers. Local tips provided if needed as well.
The flat is in a residential building, so it's not a place for loud parties - but a great base to have in a great city.