Marta is a lovely and charming host who was eager to help us enjoy Madrid. The apartment was as described and thankfully air conditioned as we arrived at the beginning of a heat wave. Marta responded quickly via email to any and all questions.
While the apartment was lovely, the neighborhood was a bit rundown. At no time did we feel unsafe but there was always garbage in the streets. It is not a bad location to visit many of Madrid's museums and sights.