This was my first experience using air BNB and I was a little nervous arriving to a city I've never been not speaking German. Arnd was great and I text him when I landed and told him I was on the way. I took the txl to hauptbahnhof and walked 10 minutes to his flat. It was easy to find. I then rang the bell at the bottom and he let me in. Arnd was very nice and helped my girlfriend carry her bag up the stairs.
The room was great. There is a private entrance and bathroom. Arnd provided coffee for us and a fridge where we kept our beer. I accidentally knocked a plant over and Arnd was very kind and cleaned up the dirt I spilled. Arnd respected our privacy and remained in the adjoining room most of the time.
Despite what some say, this location was great. One day we walked 30 minutes to the zoo, then after we took the s bahn to the east gallery. We then took the s bahn back to hauptbahnhof and walked back to his place. Another day we did our own little walking tour. We walked about 10 minutes to the Reich building and then to the Brandenburg gate. We then walked south to checkpoint Charlie and postdamer platz. We then headed east to alexanderplatz before hitting museum island on the way back. This took us all day and we walked about 9 miles but we were able to see quite a bit and enjoy the city. Arnd's location is a good starting and end point to do the loop of all the sites.
After seeing prices from all the hotels in the area, I realized this place is a steal. I would highly recommend staying here if you are coming to Berlin. It's clean, quiet and Arnd is a nice host.