This place turned out to be perfect for what we were looking for. The apartment is in a great location, very close to most sight seeing points, is spacious, well decorated and has great utility. It's exactly the way it looks in the pictures, brand new, and clean !
The apartment is located in a very happening street with many restaurants and cafe near by which are open till late hrs. Some of the main places like the Prado museum, Sq de Santa Ana (for nightlife and drinks), Puerto de sol (for shopping and sit-out square) are all at 10 minutes walking distance.
Our hosts Eliana and Diego were extremly helpful. They reached out to us asking for the flight details in advance. We were delayed by almost an hr at the airport, but they were waiting for us to arrive at the apartment (at 11 in the night) to hand us the keys and explain everything - about the apartment, nearby places for daily needs, closest metro, good restaurant listings, map guides etc. I think they're excellent hosts and perfect example to the the whole concept of airbnb. I would choose this place everytime if I were to go to madrid.