We had a lovely stay at Alessandro's apartment: 4 days and it was the perfect spot for our 1st time in Madrid. It's central, with metro, bars and restaurants nearby, and very close to other interesting neighborhoods, the room is very clean and well decorated. It's rather quiet, even though sometimes there were some noises - quite normal for a busy district in a capital :)
All in all, would recommend, and for Alessandro's kindness too!