I would stay at Margarita’s place every time I’m in Mexico City. Margarita is a lovely host, she keeps the place very clean and there is a security personnel in the building 24/7. And the location is just perfect.
The place is in Roma Sur neighborhood. Bus stations and subway stations are within 5 minutes walk, there’s a supermarket 2 minutes away and Condesa and Roma Norte neighborhoods are just 15 minutes walk. And all three of these neighborhoods are extremely safe and have tons of food options.