The place was nice, clean and everything was as it was described. No bad surprises, no tricks or anything. We didn't see Max very much because he wasn't home the first days of our trip and also because we weren't living on the same schedule as his, or just because he was probably busy working/doing his own things.
Anyway it wasn't a problem cause he's very reactive whenever you contact him for anything you may need.
The two cats living there are one of the most adorable felines I've ever met :)
The only weak point may be the noise of the trafic which makes it hard to sleep especially if you leave the window open. But Max provided us with a fan so we could still sleep despite the heat during our stay.
I would recommend it to anyone visiting Berlin, especially if you sleep easily, it's practical and pretty well located.