The place is great, a perfect location in what we think is Madrid's best neighbourhood for food, coffee, etc. It's also within walking distance or a quick metro ride of all the sights.
The space itself is exactly like the photos, compact and clean. Check-in and out was all super easy, and Maribel was very friendly and helpful.
The only thing that we would be cautious of for others is that it's an apartment building with quite thin ceilings - you can hear almost every move people in nearby/above apartments make, not talking, but any moving furniture, walking, etc. It did not bother us, but might annoy a light sleeper.
Overall we had a brilliant stay, and would definitely stay here again!