The room from Gladys is not very central located, but easy to access by the metro and in a quiet neighborhood. The room has everything you need for a short stay and has an extra key as well. I arrived way earlier in Madrid than the Check-in time which wasn't a problem for Gladys at all. She is very quick to respond and even though my Spanish isn't the best it was easy communicating with her.
I would always come back to this option when staying in Madrid because of Gladys and the price for the room.