Very nice apartment, very central, walking distance from the Prado and the Retiro park and only a few minutes walk from the Metro, but really quiet. It was plenty big enough for 4 people.
The beds were very comfortable, there was a lovely hot shower, the living room is fine and you can fit 4 round the table. The kitchen was really well equipped and there are shops very close by. Marta was great and met us to show us around the apartment and kept in touch throughout our stay. I would definitely stay there again.