Marta is a great host! One of the best that I have encountered during my airbnb stays.
Very flexible for check-in and check-out times, respectful, generous and very punctual. She also gave us local tips of what to do in the city.
The best strength about the apartment is the location and all the amenties it has to offer ( from breakfast food available to little snacks which is reflected by her generousity in welcoming her guests at her house to airconditionning, hot water, oven to cook etc)
The apartment can easily fit 4 people. The location is just perfect!! Few minutes away from Puerto del sol and Plaza Mayor. This has to be one of the coolest areas in Madrid with bars and clubs just nearby as well. We never used public transportation everything was just easily reached by walking.
All in all, I would give a 5 star ratings for every aspect and would definitely come back!!