This apartment is very well located! A few minutes walk will take you to either the Atocha train station (which has a direct train and bus to the airport) or the Estación del Arte metro station. Also in less than ten-fifteen minutes you can walk to El Retiro park, Madrid's three main museums and the Fuente de Cibeles/Ayuntamiento. It is definitely a great place to explore Madrid.
Enrique is a great host. Our flight was delayed and we arrived very late but he had no problem waiting for us. During the check-in process he will give you great recommendations of places to eat and he will even lend you a transportation card to top up and use during your stay.
The apartment was very clean and has everything you need to have a great stay. I would definitely recommend this place.