Check in was a pain.
It took me two hours to convince someone that something was wrong with the key, all this despite getting four people to try the key. Including the building doorman trying his own key. After sending multiple videos via email to let them know I was trying to open the door just fine, at hour 2. They finally got a locksmith and someone had left their key in the door on the inside.
Painful start to the stay. The experience put a damper on the rest of the trip.
The rooms decent and clean, close to all the highlights of Madrid, note that it does get loud at night with all the night time spots and bars.
Asked for a late check in at 12 instead of noon, the host agreed the previous evening and changed it back to 11 later that day.