We had a wonderful stay for the weekend at Juan's flat!
The apartment is perfectly located in Chueca, and you can easily walk to almost all of the major sites in Madrid within 15 minutes. It's in a lively neighborhood, but the apartment is in the back of the building and was very quiet at night. It's also beautifully and stylishly furnished.
Juan was quite helpful and available as a host, and was also very understanding when we arrived late at night due to a delayed train. Highly recommended!