We really liked Orlando's apartment. Its location was ideal; we took a bus from the airport and it had a stop at a perfectly acceptable walking distance from the apartment, even with luggage. Likewise, when leaving and needing to take the underground, there are several stops nearby. It was easy to walk everywhere to see the sights, and there were more bars and restaurants nearby than you need.
Orlando replied to messages without delay, and gave us good directions beforehand as to how to find the apartment, and do a self check-in.
The studio apartment was spacious, nicely furnished and well equipped, everything you might need for a comfortable stay was provided. As the evenings and nights were pretty chilly, we appreciated being able to heat the place up. As the apartment is on the 5th floor, you could hear no noise from the street below, so in this respect it was very quiet and peaceful. (However, if you're a light sleeper, it's advisable to bring a good pair of ear plugs, as I doubt there is any sound insulation in the building. You end up hearing everything that goes on around you, so if you're unlucky to have noisy neighbours you will notice it. We had someone return home in the early hours of the morning on a couple of occasions and start shouting down the phone for what seemed hours, which kept us awake.)
I don't think we could have chosen any better, and I can easily recommend Orlando's place for a comfortable stay in Madrid.