We had awesome experience staying at Jörn's place. Apartment is very big, clean and comfortable. Kitchen is very well equipped (much better than most Airbnb ones), which allowed us to cook our own breakfasts. Location could not be better - 2 min walk from subway station, a lot of really good grocery stores around, safe neighborhood. I would definitely recommend Jörn's place and will stay there for sure when we are in Berlin.