Had a pleasant stay for a week - Mayer is a fantastic host, very kind, responsive and helpful. Place was well-equipped with a simple kitchenette, spacious, comfortable, with a great Wi-Fi connection, good water pressure and hot water, convenient location with loads of taco & hamburger stands around, an OXXO with an ATM/cash machine right outside, Dr. Simi pharmacy across the street, trolleybus stop around the corner & a massive mall about 10 min walk away.
Can't really complain about the apartment, either - just one thing to keep in mind: it's an inwards facing unit, meaning you have no view of the street and amount of sunlight getting into property is quite limited (can have a bit of an impact you like waking up at sunrise like I do). But it's not an "issue"/"problem" really, just a feature of the place :)
It's been great staying with Meyer during my first week in CDMX (and Mexico, too). I can honestly recommend his place and I will consider staying with him again in the future.