Iris' flat is a wonderful place to stay in Madrid. I spent quite a bit of time on Airbnb finding it, but it was well worth it.
I felt at home immediately there. The room is very clean, quiet at all hours and nicely furnished and ventilated and the bed and bedding is of good quality and very comfortable. I had no trouble sleeping. The bathroom and shower are also very good and clean. There's also the use of the kitchen. I only used the frig for some juice and yoghurt.
The location is excellent for tourism as it is close to the major museums and good restaurants and night life. I walked everywhere I went easily.
Iris was very helpful and provided good instructions on how to arrive from the airport. She's got a phone there you can use for local calls and what you need to charge your devices. And she speaks English as well as Spanish.
The flat is on the fifth floor and had an elevator that works well. The views, though not spectacular, are good and interesting. To me the experience was much better than staying in a hotel. I had a great time and would go back there in a heartbeat.