Clean, cozy, and centrally located!
Miguel is a model host, and responds to messages very quickly.
We found the apartment spotless, and the place had a "home away from home" feel.
It's a block away from a metro stop, and a short walk from Plaza Mayor. The infamous Sunday flea market "El Rastro" literally begins at this building's doorstep.
Personal fave: the kitchen had everything we needed to prepare meals.
Downside: I think there's a daycare/nursery nearby? During the day you can hear babies crying, even with the windows and balcony door closed. I only noticed because I was sick one day and decided to stay indoors to rest.
TL;DR - this is the best bang for your buck. Decent apartment, good location, great host.