We stayed 3 nights at Günther's place. The apartment was very clean, and just as he described it. The metro station is just a few minutes walk away and nearby there are numerous supermarkets, bars and restaurants.
Cons: It is situated in the 3rd floor - it is an old building with high headroom without an elevator. The stairway is not the prettiest either. In november it was also quite cold.
Pros: for 2 people the space is enough, the bed was comfortable and the kitchen was well enough equipped. Günther also replied instantaneously to our messages.
We recommend to stay here. :)