Location, location, location. This apartment provides a very close walk to a lot of local as well as touristic interest points. Madrid is a place full of history as well as tapas bars and few minutes from Carlos's apartment. We were a family of four and the apartment was a little small, yet my kids compromised and we had a great time. The apartment was fully equipped although if you want to experience the Spanish living, they do all their meals in cafeterias and tapas. El Corte Inglés has very good food through out the day ( most restaurants close the kitchen service between lunch and dinner). Walking is the way to visit Madrid and we did plenty of it and towards the night we got a taxi ( very inexpensive for a family of four around 5 euros to Carlos place).
We met Carlos, a super nice person, he recommended very nice places to eat and help us with the transportation to the airport ( we are very grateful we left on a Saturday at 5;20 am).
I highly recommend this place for its location, cleanliness and an extremely efficient host.