We were in Santiago's apartment from 6/19 to 6/23 (3 people) and we really enjoyed our time there. Communication with Santiago was excellent (he left a bottle of wine for us)
Highlights: private parking (used our rented car for a trip to Segovia), really close to the 'Museo de la Reina Sofia' (do not miss 'Picasso: Path to Guernica'). There are 2 Metro stations close but we do not use them because taxi is cheap in Madrid. Thanks Santiago we will be back