I echo the positive comments left by others. It was a wonderful apartment and our group of five were all very happy. Emilio was extremely helpful both before and during our stay, and was very communicative as well. Directions to the office and the apartment were precise and our taxi had no trouble getting us to the locations.
The apartment was perfectly clean, and is located in a cool and convenient area. Lots of places for food and drink in the close vicinity. It was also an easy walk to many of Madrid's tourist attractions. Emilio also provided us with some personal recommendations, which were helpful to us.
Overall it was a great place to stay to kick off our trip, and I would certainly want to stay there again if I'm ever in Madrid in the future.