The apartment is amazing and looks exactly as on the provides images. Around the corner is a large street with tons of restaurants and coffee shops. But the street where the apartment is located is very silent. Two different metro stations in walking distance connect you to the city. But we were walking most of the time.
Getting to the apartment from the airport is super easy. You can use the C1 train from T4 to Atocha Station which is approx 5-10 minutes walk away and also the cheapest connection available (2,60 Euro per direction and person).
Emilio is a great host. Getting the keys and returning them was super smooth. Also he gave us a lot of useful tips for getting around. We can highly recommend him.
The apartment also features a Nespresso machine (not only coffee maker ;-) and an Apple TV which makes it even more comfortable.
On my next stay in Madrid I will definitely book this apartment again!