I highly recommend Claus' apartment. It's very comfy, there is everything you may need and it feels like home. The area it's Prenzlauerberg which is probably one of the best of Berlin. Lively, friendly, full of cafés and restaurants, the best place to stroll around. The apartment is located in a nearby street with the big advantage that is not noisy. Should I come back to Berlin, I'll definitely choose Claus' apartment again.