The apartment location is perfect, next to the lively street with restaurants and cafes and Nollendorfplatz U-bahn station, but on a quiet side street, which means that the apartment is quiet and we slept very well.
The internet is very fast and reliable, the apartment is warm and has two big TVs. The kitchen has all you need to cook a few easy meals for a short stay.
the communication with Ulrich was very good, he was responsive and kept checking up with us to see if everything was fine.
I would really recommend this apartment as a base to explore Berlin.