We enjoyed our stay here. As a group of 3 the place was comfortable enough and a good fit for our needs, wanting to visit everywhere possible in Madrid and then relaxing back at the apartment.
Location very well connected, nearby several public transportation stops and also within walking distance of most of the city center. Really nice breakfast spot just across the street. As it is on a first floor there is a long flight of stairs up to the apartment and there is no elevator, but luckily for us this was no problem at all.
Everything was as described, the apartment was neat and clean. Visiting during the winter was also not a problem, as the heating works just fine.
The hosts are very responsive and good communicators. Questions are answered soon and sufficiently, and they also make interesting recommendations.
Overall, a nice stay. Would totally repeat!