My stay with Nina was great! When she says that the apartment is centrally located, she's not kidding! The U-Bahn is literally steps from the front door and there's plenty of restaurants/shops etc. within walking distance. Despite being in such a heavily trafficked area, the apartment was nice and quiet, and I slept very soundly. Nina was a great host, despite the fact that I booked the room at the last minute. She answered all of my messages very promptly and overall I had a great experience. A word of caution, however, the apartment is not very accessible (you have to go up many flights of stairs to reach the apartment and then the bed itself is a bunk bed) so this might not be the apartment for you if you or someone you're traveling with can't navigate stairs well.