We were looking forward to staying in the apartment but had a few small concerns based off of more recent reviews. I would say that everything in these reviews is completely accurate.
Communication with the company was terrible - they didn't reply until the day before check in. It made me very uneasy to have to send our private details and passport information via text and email instead of just through Airbnb. This didn't make any difference because when we arrived at the apartment the guy meeting us took further pictures of our passports on his (personal?) phone and required the details again, despite already having the info. Besides that, he was very friendly and welcoming.
The location of the apartment is perfect - central to various metro stations, near to several supermarkets, restaurants and bars without being noisy at all. The neighbourhood is very clean and upmarket.
The apartment is exactly as described and pictured - but I would say it's not as fresh and new as in the photos. Nothing major but it needs a few touch ups as the walls were really scuffed in places and the table in the living room has obviously had a hard life! It was great how toiletries and supplies for washing dishes were provided. The apartment was also super clean.
The shower is great but the drainage for the shower is absolutely awful. After even a five minute shower I was up over my ankles in water with my toiletries floating all around me - not relaxing! They definitely need to fix this.
Another review mentioned the small bedroom having thin walls and being loud - we found this to be the case with both of the bedrooms, but only around 11pm and 8am. The rest of the time it was silent - and the building was really lovely.
At check out we just had to leave the keys on the table in the apartment - we then realised this would be problematic because in order to open the front gate and leave the building you have to use a key from the inside. So one of us had to run downstairs and hold open the gate, whilst the other person took the keys back upstairs to leave on the table. If you were a single person this would definitely be a lot more tricky!
So in conclusion we really enjoyed our stay in Madrid and found that the apartment met our needs. It wasn't as a great a stay as apartments in similar price brackets in other cities, but perhaps accommodation in Madrid is just more expensive.