The apartment is perfectly located in one of the most hip areas in Madrid. Despite its location in a nightlife area, the street it is on is in fact very quiet and residential so we enjoyed the location and proximity to most attractions in Madrid while living in a really quiet apartment.
The apartment is nicely decorated with recent modern furniture, kitchen accessories and appliances (eg. an espresso machine). It was an excellent home base for our 5 days stay in Madrid.
Lorenzo, the assistant of the apartment owner, who met us when we arrived, was very nice, helpful and fun to talk to.
Our only complaint was that the original description did not include any mention of late check-in fees which we only learned about a few days after making the reservation (30 euros for checking in after 22:00 and 50 euros for checking in after 24:00). Had we known about this in advance we might have booked a different place. Although we completely understand that Lorenzo, as an employee, had to be compensated for waiting for us until late, we would have liked to know this in advance and not after we made the reservation.
Overall, the apartment was great - great location, very nicely appointed and decorated, and, with the exception of the late check-in fees, great communication with the hosts.