If I can describe So's place in one word it would be IMMACULATE. The place is cozy and really clean!
So, without a question went the extra mile when I asked if the place had a heater, which it doesn't, but she offer to let me use an electric portable heater which she personally delivered upon my arrival. She also answered my messages really fast.
I strongly recommend you to stay at So's place, its location couldn't be better, in the heart of Polanco, walking distance to everywhere. I actually went to the Auditorio Nacional for a concert one night walking back and forth, the area is incredibly safe with a lot of shops, cafes and restaurants around.
The only inconvenience which actually it's not considering what you're paying, is that the apartment is on a third floor and the building doesn't have an elevator.
Finally, a personal recommendation to every US traveler visiting Latin America, and it doesn't have anything to do with the place where you stay at: Please, please, please, bring your own toilet paper. Don't forget it. Trust me.