We had a great time in Madrid and we felt very comfortable and relaxed at Mariano's beautiful apartment. It has everything you need, it is quiet, clean and bright. Each room is filled with interesting pieces of art. I did not get the chance to meet Mariano in person since he was off for holidays while we were in Madrid, but he kept pretty much in touch with us during the stay. Please note that the apartment is situated in an area of Madrid (city centre) where you are not allowed to enter with your car, not even to unload your suitcases or you might get a fine. I hope Mariano took care of it as he promised (I wish he could be more responsive), by asking the police to remove the fine since we entered the restricted area only for 10 minutes in order to unload our luggage. If you don't have a car, then you have no problem at all!
Internet connection is really good, but please note that it doesn't reach the living room, it works perfectly in the bedroom. Overall we had a great stay and I definitely recommend this listing!