This is the kind of place that makes me feel at home in Madrid.
The location is unsurpassable: a 2-minute walk from Puerta del Sol where you can get the subway to everywhere (you are literally in the heart of the city), you are close to the main museums, plazas, and avenues. Plus, the host is nice and responsive, and keeps the apartment neat and comfortable.
The building is quiet, clean, and there is a lot of privacy. The apartment is bright and spacious, with a modern style. The kitchen has everything you may need for a stay.
I'm definitely booking this place again next time I go to Madrid.