The location is superb. Right across the road from the Reina Sofia, and within walking distance of everything you'd want to visit in Madrid, be it the Prado, El Retiro, Gran Via, Plaza Mayor etc.
The place itself is a good size for 2 people, it's clean, it has a fully functional kitchen with an induction cooker, full set of utensils and cutlery, a microwave, a kettle with coffee, tea and sugar.
Javier was waiting for me at the promised time even though it was a bit late, explained the procedure for the keys, explained the ins and outs of the room, and helpfully described the local area, eating places, markets etc.
I'd happily think of coming here again or one of Javier's other properties around the same area.
Great stay!