I stayed at El Tesoro's apartment for a single night, I was in town for a Real Madrid game. The location was perfect for my purposes - 20 min walk away from Santiago Bernabéu and a few minutes walk from the metro line that goes to Atocha (I arrived by train).
The apartment is located on a quiet street, there was no noise whatsoever, both during day and night. At the same time, there was no shortage of restaurants and grocery stores in the area. Esther provided me with useful instructions on how to access the apartment, and the process was very easy. The apartment was small but had everything I needed for my stay. What jumped out to me was how clean the place was - it was sparkling!
Overall I really enjoyed my stay and will definitely consider booking with El Tesoro when I'm back to Madrid for football games. Highly recommend choosing these apartments - the value for the price is hard to beat!