We spent 5 days in Berlin in July 2013, amazing city! Robin's flat has perfect location, close to main landmarks. Most of the time we walked to our destinations or took a short couple of stops subway/tram ride. The area is very lively, lots of cafe, bars and small boutiques.
The flat is modern, clean and nice to stay in. Robin is very friendly, easy to deal with, flexible with arrival time arrangement and provided lots of useful information; it was a pleasure to chat with him. I hope to return to Berlin sometime in a future and will be happy to stay at the "Kastanienallee appartment".