A few others have said some very nice and accurate things about this property. They are all true. I wanted to add four special notes.
First, the location is outstanding. It is central, yet very quiet. To give an example, on our first night, there was a festival in La Latina: Wall to wall people, lots of noise, tons of drinking. But none of that could be heard in the apartment. Quiet as could be for central Madrid.
Second, the apartment looks better than the pictures which are posted. It is well stocked, has everything you need and has all the dishes and cookware that you'll need. It also has two exposures, so by opening the windows, a lovely breeze kept the apartment cool, even as Madrid boiled.
Third, Javier was wonderful! Some apartments in Madrid require you to go and pick up a key from a central office, adding lots of time to the check-in. Javier was not only there to greet us, he arranged for a taxi to pick us up from the airport, stayed at the apartment when our flights were delayed and even arranged for a taxi to take us to Atocha Station. He showed us the apartment, gave us directions to the supermarkets and all around made our stay wonderful.
Fourth, the bed is very comfortable. Its a king sized matrimonial, so its not two mattresses pressed together, but a single one.
A wonderful stay, all around. This is our third visit to Madrid: We stayed in the Salamanca and Chueca before this. This is easily our favorite location and when we come back, we would hope to stay here.