Overall this is a very good apartment with an outstanding location in the Polanco, Miguel Hidalgo area. Numerous Embassies are within a few blocks, a great small park and s great walking "mall" along Horacio Blvd. There are many great restaurants with a 5-8 blocks radius, just look for the Intercontinental Hotel and head in that direction and you will find them.
The apartment building is quite quaint and cozy. The apartment in general is nice, there are a couple of minor issues that most travelers would find annoying; there are 1 1/2 baths, the 1/2 bath is quite narrow, but very functional, the full bath has some design issues = the shower door opens towards the toilet and you can't open completely. The shower head angles that you have to stand next to the wall to get the full shower on to oneself, bad design. The kitchen is adequate, if ONLY, you pal to make coffee or sandwiches, it needs more "work-space" if you plan on cooking a real meal. The stove/oven and the refrigerator are large, something I have found in Mexico some don't.
Overall I give the El Ruiseñor AirBnB a solid 8 on a scale of 1-10, with 1 = Horrible and 10 = Outstanding.