The apartment itself is wonderfully located very much in the heart of Madrid. Theres a welcome pack suggesting local restaurants and bars which is a nice touch. Its a charming apartment, nice and clean etc with towels and basic amenities. Not really great for more than 2 people; try as we might we couldn't get the sofa bed to work, we resulted in my sister having to make do with the sofa.
We were also given the wrong street number for the apartment which wasn't a great start, so double check that! but i would recommend it in general.