Alex's apartment was exactly as described. We enjoyed four nights there and found it to be a quiet area with plenty of options for eating, drinking, transport and sightseeing within walking distance. It's possible to walk there from Alexanderplatz and took us only about 20 minutes with our backpacks on. There is also a big supermarket directly across the street, which is open late.
The bed is big and comfy, and so was the sofa in the lounge room. We were made to feel at home when we arrived. Alex trusted us with her apartment for a few nights when she was away for the long weekend. Excellent host and clean, modern apartment. Recommended!