I enjoyed my stay at this place. The only small issue I had was when my reservation was confirmed and I didn't get any messages in several days. I messaged asking to confirm me that all is ok and after that the messaging was quick. Hermann wasn't around but his friend Sasha was there to welcome me and giving me instructions when my Google maps wasn't working properly. He was very kind and welcoming.
The place was nice and clean and had all I needed. It wasn't shiny new but more like nice and homey. The balcony is nice for sitting in the sun even though you can hear the street noises. The area is a bit trafficy so I wouldn't recommend this for someone who is a light sleeper. Also the house does get quite warm during the daytime and in the morning, though I was not bothered by this too much in the +20 spring weather.
The area is ok: like I said a bit trafficy but there are restaurants and cafes around. The Ubahn is right around the corner and Ringbahn station 3 min walk away. The trip to the heart of Berlin takes 30 min, which is not too much if you spend the day around Berlin and go back only to sleep. During the weekend the public transport runs late but during weekdays you might have to consider grabbing Uber or taxi back if you want to stay a lot after midnight.
All in all I enjoyed, and if the slight traffic isn't an issue for you this place is good value!