Definitely book this Airbnb if it is available! My friend and I stayed at Estefania's place for 4 nights and really enjoyed everything about the experience.
Estefania is an amazing host! She is very kind and was easy to communicate with, whether or not you have a data plan (I messaged her via Airbnb and text/iMessage while my friend used WhatsApp). The apartment was spotless our entire stay and Estefania provided all of the essentials. The room had a very comfortable mattress and super efficient air conditioning and wifi. The bathroom was also great and had a wonderful shower.
The location cannot be beat! In our 4 days in Madrid, we never had to use public transportation. There are plenty of buses and nearby train stations, but we found the city very walkable. We were glad we chose this area as it is very close to the museums, park, palace, plazas, etc. and had countless restaurants nearby. Surprisingly, the apartment was remarkably quiet all weekend, despite being in the city center. The view out the window is amazing and our time there was perfect. I cannot recommend this place enough!