Fun and funky apartment in the center of Madrid with homey feel. Very close to transportation, shopping and many attractions such as the Royal Palace. Metro stop Opera is within short walking distance. The place itself is well equipped and had most things we needed - we could cook and do laundry. All windows face inner yard so it's relatively quiet, and one of the bedrooms doesn't have any windows at all - make sure you're okay with that.
The hosts communicated well, and arrival was smooth.
We arrived with a car, and many parking garages shown on the map around the place do not actually exist.
The best option I figured out is "Parking Palacio de los Duques" aka "Parking Opera" at Cuesta de St Domingo, 5. The garage is tight, but it's very close to the apartment. They charge 29 euros per day. Hopefully this helps someone.