We enjoyed our stay at Berta's place. Although it is a very small studio, the space is well used, with a nice design, everything is brand-new and sparkling clean and the bed is very comfortable. Plaza de Castilla Metro Station is just around the corner, with good connections to the City Center and Chamartin Railway station is a 15-minute walk away (from here there are direct trains to the airport, but also to Avila, Segovia, El Escorial or Aranjuez - for those looking for a day trip from Madrid). There are nice cafes and restaurants, as well as supermarkets nearby.