Fantastic apartment in great location for seeing all the sights! Right next to metro (which we only used to go to Chamartin train station to go to Segovia). Short walk to Atocha Train Station to go to Toledo. Short walk to Parque de Retiro, Museo de Prado, Plaza Santa Ana and Plaza Mayor. However we walked to Palace on the west too. Open top city tour bus at bottom of road.
The apartment is immaculately clean, spacious, well equipped, comfy beds, great showers, very modern, tv with Netflix app for the kids (own login), great place to return to after a busy day. Also felt very safe as secure front entrance and secure door into apartment. Also felt safe in the area. Supermarket about 1 min away which stocked great selection.
Great service also from agency who service the apartment from communication before you arrive, arrival which the lovely Marta met us, let us leave our luggage as we had arrived early, showed us the apartment, set us info about Madrid and also provided us with a contact if we had any problems (which we had none).
All in all a great place which I highly recommend and would return to!