The apartment is spacious and clean, with two bedrooms, a kitchen area with basic pots and pans, refrigerator, stove, microwave, and a common area with couch and table with enough settings for four people. There is no heating, so it can get a bit cold during December, when we were there (16C/61F inside), and we probably could have used an extra blanket. There is hot water heater and tank next to the kitchen sink, which has reliable hot water. The bathroom sink has only cold water at the tap and the shower's hot water is intermittent.
Our host was generous and understanding when a flight delay made us arrive after 1 am in the morning, and he allowed one of us with an evening return flight to leave a suitcase at the apartment until the next guest needed to check in.
The location is good, below and next to a highway overpass, so a bit noisy, but within an easy and pleasant walk (along a park) to the Metro (a straight line to the Zócalo) and not far from the lively Coyouacán neighborhood, with the Trotsky and Frida Kahlo museums. The apartment complex is secure (external gate) and the area seems safe. There is a great breakfast spot, Rafaella, with baked goods and various egg dishes and espresso coffees and teas, a 5-minute walk away.
Judging by the reviews, most of the guests seem to be Spanish-speaking, and the instructions for using the apartment are in Spanish only. We managed to communicate in our mediocre Spanish and were happy with the experience overall.