Arzu and Tom's apartment is absolutely amazing and they are some of the most helpful we've encountered on our trip so far. We only met Tom, but he filled us in on everything in the area and recommended places to eat and shop as soon as we arrived. The day we left, we were taking a night train and they held onto our baggage for us long after the check in time so that we could have another day to explore Berlin unburdened by our heavy back packs.
I would definitely recommend staying with Arzu and Tom. The location is excellent, they were incredibly helpful and you will have an amazing time.