I stayed at Javier's place for 4 nights in December. The view from the apartment is amazing (I especially liked it a dawn) and the apartment itself is open-space, spacious, and well organized. The bed was comfortable. Be aware that like in (almost) all CDMX, there is no central heating and nights can be quite chilly in the fall/winter.
There is a spacious gym in the basement, although the space is mostly empty: a few cardio machines in good conditions, a multi-purpose pulley-based resistance device, and a few dumbbells up to 50 pounds—enough for a quick morning workout. I used the gym 3 times during my stay and I was the only one working out.
The apartment is located in the Centro histórico of CDMX, which is busy most of the time, with plenty of eating options at walking distance.
Communication with Javier was quick and clear.