We were pleased with our stay. Everything worked perfectly. The location was great, easy access to the subway, Puerta del Sol, Plaza de Santa Ana and the greatest museums. The apartment itself was very clean. Carmen was a great host. She kindly agreed to receive us almost midnight.
Two minor points of criticism: bathroom very small, especially shower's area. This might become a problem for tall people, like my husband; the apartment is on the second floor, no elevator, which can be a problem for people with limited accessibility.