Apartment is in perfect location. 3 min from Metro station, 5 min from plaza Callao. Two bedrooms and 2 bathrooms are big advantages. Check-in with locker also was really useful, because we came after midnight and most of apartments wants extra charge for late check-in. I can really recommend it.
Although there was some small disadvantages. It is not so bright like on the picture and windows looks on the inside patio with laundry hanging just outside. Apartment wasn't perfectly clean - there were dust on the shelves and floor next to the bed. Some of the neighbours were partying late, but it was weekend and we stayed late as well, so it wasn't big problem for us.
In short, if you are looking for great apartment to spend couple of days in Madrid this is good place for you.