The host: communication with Ivette was very good. She's very responsive and nice, and is on top of her game.
The building: it's well located, stores, small coffee houses, places to eat and convenience stores are all around. Walking distance (10 min) from Insurgentes, close to the WTC. It's one of the most important streets in the City and you can get everywhere from there. The building is a bit old, but clean. It's located on a busy street, and the neighborhood is safe.
The apartment: it's on the first floor (not the Ground floor). It has floor-to-ceiling windows wall-to-wall along the dining room and bedroom, so it can be a bit noisy, especially in the morning at rush hour, or if loud trucks or motorcycles drive by at night, when everything is quiet. The positive is that you get a ton of light all day.
The shower is not the best, not much pressure and hot water doesn't last long, so you need to shower fast; and I mean 3-minute fast. There's no microwave, which is a bit inconvenient. The remote for the TV was not working. I was very busy and didn't tell Ivette until after I had left. She may have changed it by now. Internet signal worked very well and with no interruptions.
All and all, it was fine for me. If I go back to Mexico City alone, I would stay there again. I know what to expect now.