The appartment in itself is great. It has everything one might need and it is super clean.
The building is located very central and in a super busy and noisy street, however you hear nothing from the appt.
The checkin process was smooth and the appartment is run by a company which means that you should not expect personal communication.
What is more they sent me automated messages suggesting random charges (100 eur deposit to be returned at the end, 30 eur late checkin fee). These requests are not related to anything mentioned in the Airbnb webpage. For this reason, when I asked them to send a money request through Airbnb they did not proceed. It felt a bit weird because -since this was a company- they were non conflictual and did not even respond when I informed them that this is not allowed. They just did not push with the charge. In that sense, even though it was a headache to get their messsages, nothing happened in the end.
Furthermore, the first night we were confused and tried to enter a wrong appt in the building. We honestly hope this did not create any problems for them, as we annoyed the neighbors by mistake.
Overall, I suggest staying there if you want to be in the center of Madrid literally, but be prepared to not let them scam you.