Although this was my first Airbnb experience, I can say that I couldn't have had a better one. Antonio was absolutely great, always available and with a perfect sense of welcoming.
His apartment may be small for some, but even for 4 people is good on my standards. For a couple is perfect. It has a clothes and dish washer machine, strong water pressure and quickly heated. AC works fine, TV is great and Wi-fi too.
The location is central, very close to subway and train stations, set in a calm neighbourhood, plus Retiro Park was literally less than 10 minutes away.
Overall, there is no other place for me to stay if or when, I come back to Madrid.