We had a great time at Sören's place. It was easily accessible from Berlin Hbf. The apartment itself is on the street-level, meaning that the entrance door opens directly to the street. The street is not very busy so we were not too bothered by the noise.
The location is very close, if not on top of, the Berlin Wall. It feels interesting to stay there on the border between the old East and West. The neighborhood is quite hip with nice restaurants and cafes (to the south of the apartment).
The apartment itself is very well-equipped and was very clean upon arrival. The amenities were in great condition as well. We had access to a smart TV so we could use Netflix (or other services) on top of German TV and TV+.
We stayed at his place in early July when it can get quite hot in Berlin. Since the apartment mainly has one more window, it can get quite hot too. For this reason we kept the curtains closed when we were outside.
Overall I would recommend staying at Sören's place. He was very responsive as well, so I would say it's a great value for money!