Our stay at Salvador's place was great.
The location is perfect:
one step away from the center of Coyoacan with all sorts of cafes and restaurants nearby, and only 10-15 minute away (walking) from the main sights of the area (e.g. Frida Kahlo museum, Viveros de Coyoacan). At the same time, it is quiet without loud bars or restaurants in close proximity.
The apartment was clean and had everything we needed for our stay, including drinking water.
We had a few issues (warm water...) that were swiftly fixed immediately after we reported them.
I would recommend staying at Salvador's!