Alfonso's place is amazing! It is in a great location: quiet, central, in easy walking distance of several attractions (San Miguel market, the royal palace, Gran Via, Parque del Oeste are all really close, and you can also quite easily walk to the Prado etc.); there's a supermarket on the same street, and several good restaurants within 5 mins walk.
The apartment is extremely clean and stylish, and I was very comfortable there.
Finally, Alfonso is a brilliant host: check-in was easy, he replied to messages quickly, and he even went as far as to buy me an office chair because I told him that I would be working on my laptop a lot during my stay. I would not hesitate to stay here again - a perfect Airbnb experience. Thanks Alfonso!