I needed a place in the center of Madrid for 2-night stay, and it's hard to be more centrally located than Calle del Príncipe. There are abundant restaurants, bars, cafés, and clubs within steps of the front door. And despite all of the activity, this flat feels like it's far above all of the street noise, which is considerable in this part of the city.
The space is fairly small, but well-designed and configured. I liked both furnishings and decoration. The living room and bedroom are on separate levels, with a spiral stair case connecting the two floors. Guests should be aware of the climb before booking a stay here. The bathroom is on the second level, and my only observation is that the ceiling is very low for tall guests--I hit my head a couple of times before learning to negotiate the space. Nonetheless, I enjoyed my stay in this flat.