The location of the apartment is simply superb: whole downtown Madrid is at your feet, literally. If you want to truly feel the vibrant city, this place is for you.
In the apartment there are some ergonomical shortcomings: very small bathroom (we were in 5), and even smaller space at the basin in the bathroom because of bathroom cupboard. Kitchen is quite narrow also, with little space for stuff to store.
Otherwise, we had a lovely time there. All kinds of shops and facilities, including car rental, are at short walking distance from apartment.