This apartment was one of my favorite Airbnb stays so far. The location can't be beaten as far as quick access to the main attractions in Madrid and easy access to the metro if you want to get out of the touristy area.
Everything was very clean and Emilio went above and beyond with communication. We tried a few of his food/drink recommendations and he even helped us figure out the washer in the unit with very detailed instructions.
My only small complaint was the check-in process was a bit confusing. We weren't aware we would need to pick up the keys in a different location than the apartment (it's a 10-minute walk between the two places). We ended up getting a taxi from the train station to take us first to the key pick-up and then to the apartment. It turned out to be an easy process, but it was a little inconvenient. I would do that over and over again if it meant getting to stay in this awesome apartment though! Don't let this deter you, but it's something to be aware of.
My partner and I can't wait to go back to Madrid and stay here again.