Carmen's apartment in Madrid is very nice, small, but cozy. We liked our stay there a lot! Carmen was very helpful and promptly arrived to meet us when we came earlier than we had told her before. Her English is not great but we came along well. Her son sent us the WiFi key promptly - thanks for that!
The location is great, it is very close to Antocha and Antocha Renfe stations, where you can get an easy ride to the city. There are also some nice bars and restaurants in the neighborhood that can be reached on foot. We'd book the apartment again!
You only need to be aware that the bathroom is accessed through the main bedroom. Staying there with more than two people needs a little arrangement, but is of course feasible.