Had a fantastic stay at Jonas' flat - would really recommend to anyone visiting Berlin. The location is ideal - you are between Kreuzberg and Neukolln (two best places in Berlin in my opinion) and really close to the canal which is beautiful. The flat was perfect - incredibly clean and a really comfortable place to stay (it was snowing and -6 degrees in Berlin when we were there, and the flat was lovely and warm!). Check-in/check-out very easy, and well-communicated by Jonas in advance. In all - highly recommended!