I stayed in Sabrina's apartment with two more friends, everything was amazing. Sabrina was very nice and friendly and helped us with all our questions. She also was very flexible with check in and check out time which helped us a lot. She showed us a map and helped us to get around the city and suggested some good places.
The apartment was very nicely decorated, clean, cozy and the location is perfect, walking distance to everything you need.
Definitely coming back next time in Madrid!