The good: the apartment is really nice, everything you need is available - multiple towels, a carafe of water, etc. Gonzalo is great, super nice and helpful, and the apartment is incredibly close to the metro.
The bad: if you're trying to be in the touristy area of Coyoacan, this isn't it; it's not too far, but you do have to cross a couple huge streets to get there.
More importantly, Gonzalo asked me early in the day what time I would arrive, but he wasn't there, and didn't tell me he wasn't going to be. Luckily a neighbor let me into the building or I would have been standing alone on the street with my luggage at night. Gonzalo was at a concert so his dad, who also lives in the apartment, came home early from drinking, completely plastered. This could have been really bad but ended up being ok. And then his dad drunkenly asked me to call his girlfriend and tell her that he was handsome, which made me uncomfortable. I'm certain he didn't mean anything by it, and luckily his gf didn't answer, and the rest of my stay was perfectly nice, but it wasn't a great start to my stay.