Well, that was my first using AirBnB and I'm 100% satisfied. Roberto is a great host and he provided me all the needed information to get he best of Madrid. The rooms are clean, well furnished and the apartment is definitely well located in the earth of Madrid.
On top of that, the Mercado de la Paz is at the corner. There you'll find some delicious food and Spanish specialities.
To sum up, I strongly recommend Roberto's flat for anyone who has the willingness to discover this authentic and vibrant city.