If you want to get close to the heart of Mexico City, Marcia's place is definitely the choice. It is close to most historical and cultural sites in Centro Historico, walking distance to nearby metro stations, restaurants, grocery stores and bakeries. However, being at the center of the city also makes the place vulnerable to street noise at night, which maybe troubling to people who have difficulties to sleep. Personally, this did not bother me at all.
Marcia and Vector took care of my stay at full length. Marcia was easily reachable via messages and the guide she prepared at the place really helped me a lot during my stay.
Hope to come back to the city in the near future since there are still so much more to explore!