We (my husband and myself) stayed in Nader's flat for a week in January and loved it. The location is ideal: very close to everything (shops, restaurants, tourist attractions and the metro); although the surrounding streets are busy and noisy, Nader's flat is quiet at all hours. There is a wonderful little supermarket across the street which is an added bonus.
The flat is sunny and nicely designed with ample closet space. Bed, couch, kitchen table...all very comfortable. I suggested to Nader to add some rugs to warm up the space a bit!
Hoping to go back to Madrid next year and will definitely stay here again...great experience!