Mariola's apartment made our trip to Madrid truly worthwhile. Nice, clean, and exactly as shown in the web photos. Completely private with a private bathroom. It is in a great neighborhood surrounded by a nice collection of bars and tapas restaurants, but the apartment is well-enclosed so that it remains entirely quiet. The apartment is also right near a metro station (Bilbao), so you can reach anywhere in the city within minutes. Extremely convenient.
Mariola is a very nice caring host; she was very quick to respond to our inquiries and provided satisfactory answers to all our questions (in perfect English).
All in all, it was one of the best experiences we had. We recommend the apartment highly!