I had a great stay at Rene's flat in Berlin. It's a really lovely place, and very well situated: it's right by grocery stores, a highly connected subway/tram stop, cafes and restaurants, etc. Not a touristy area at all which I view as being a positive thing. Andreas and Patricia who live in Rene's flat (at least at the time of our stay) were extremely welcoming and gracious hosts. Rene himself was highly communicative and helpful despite being at his other home in a different time zone.