My sister and I stayed at Marcia's place over Christmas. It was the perfect spot for our first trip to Mexico City: walkable to Bellas Artes, the San Juan gourmet market, museums, and so much more. The apartment was exactly as advertised and Marcia was very quick to respond to our questions about check-in and check-out procedures. It is next to a bustling pedestrian avenue, so I recommend ear plugs if you have trouble sleeping with outside noise. We used the fan Marica provided, and we had no trouble.
I heartily recommend the apartment to anyone staying in Mexico City!