Carmen is a great host, clear communication and we always get timely response for our queries. Camillo (guy we met for check in) is punctual, friendly and helpful, and speaks fluent English.
Apartment is just beside the Atocha train station, the surrounding is a bit too lively to our taste, but its undeniably centrally located with easy access to most of the things you'd need.
Room is exactly as advertised in the photo, clean and well equipped with amenities (no washing machine provided but not sure if this is the norm for Madrid Airbnb).
In general a great value for money choice, would recommend.