Great apartment in a quiet, well-established neighborhood. Terrific place to be if you want to be in Madrid without being in the middle of the tourist district. It's located in more of a "my affluent grandparents live here" neighborhood than a hip or trendy young people's neighborhood. Easy walking distance to the park, small grocery stores, and less than 10 minutes walking to the Metro. Write down the address to show a taxi driver if you have difficulty correctly pronouncing the name of the street like I did.
The apartment was great for the 4 of us -- Dad, sister, husband, and I -- as we needed 3 bedrooms. Plenty of space in the living room to chill out after a busy day of exploring the city. Beds were very comfortable, and the A/C was a treat. If the windows are open, sound echoes between the buildings so you can hear whatever TV show the neighbors are watching. Very quiet when the windows are closed.
The kitchen was pre-stocked with bread, butter, wine, coffee, juice, oranges, and water. Such a thoughtful touch! Having a kitchen and washing machine was a game-changer for our week and a half-long trip. Clara was very responsive when there was an issue with the water heater. The onsite building manager took care of the issue within half an hour of us returning to the apartment.
Great place to stay for families. I highly recommend it.