Me and my family spent one week in Uwe's flat and, even if I didn't meet him in person, he was really nice and always available to answer my emails.
He sent us the key of his flat at our home one week before our arrival.
Communication was great and the flat was nice, located in a nice family neighborhood full of vegan restaurants :) & full of babies and strollers...
If you come with heavy suitcases, beware that the flat is located at the third floor with no elevator. Access to the center from Uwe's flat is really easy.