Max's place is just like the photos - impeccably clean and cozy. Since it's underground, it stays cool even during the summer (although there's also AC if you need it). The wifi was fast, and I had all the things I needed to cook food. There's a shared washing machine upstairs that I used to do my laundry. The location was very quiet and convenient - super close to the heart of Madrid, and you could walk to most places easily.
Max was very responsive and met me on the day of my arrival, as well as on my checkout day. Overall it was a great place to stay!