Excellent communication from Jens, very friendly and helpful host. I had to book the apartment very quickly due to a previous not so successful booking with someone else, and he came to my rescue incredibly quickly. He gave me the keys within 45 minutes of me calling him and booking the place. It's a simple, but clean and functional flat. Really convenient location at Nollendorfplatz, shops, cafés, restaurants and lots of bars nearby. Metro is about 5 mins walk, and it's one of those U-Bahn junctions from which you can go basically anywhere.