A clean, spacious and well located apartment. Check in and check out could not be easier and all communications with the host were excellent, they provided quick an attentive responses to all requests.
My only comment will be that although the location (right on the plaza) is very convenient to explore the best of Madrid, it makes the apartment very noisy and partying outside goes on all night long (literally). So great if you are planning to party too, but not so much if sleeping is in your plans. Bring ear plugs!!!