The appartment was very clean and modern, and conformed to the photos on the website. Kitchen had a proper-sized fridge and cooker, which was useful. Beds were comfortable and the heating system worked fine.
The appartment only has windows into light wells, so there was no noise from the street, but quite a bit from other appartments. It's on the third floor, and there is a lift, but this is very small, so if you had big suitcases it could be a problem.
Location was OK, although we hadn't researched it properly and didn't realise we'd have to walk for 15-20 mins up a hill to get to the centre + restaurants, which wasn't ideal with children. We ended up getting Ubers most of the time. That was our fault due to not looking at the map properly initially!
Overall, the stay was OK. We felt it lacked that personal touch that other Airbnb's have: there was no host to greet us, no information about Madrid in the flat such as a map, and no basic supplies to start us off such as milk or bread.