Staying at Han's accomodation was beyond ideal! It's located in a very quiet and friendly neighborhood with great places to eat (really recommend Malafemmena for amazing sourdough pizza, a lovely local deli on the corner of the street and the Zig Zag Jazz Club).
The transport links are perfect for anyone wanting to travel in and out of the city with a U-Bahn a 2 minute walk from the house - it takes about 15-20 minutes to get into 'central' Berlin. Their are plenty of easy links to both airports too on either the U/S Bahn or the bus.
Han's sister really kindly waited for us to arrive at the house to welcome us and make sure we had everything we needed. Nothing was too much trouble! The house is so charming and has so many lovely touches (a fellow avid art fan it seems while I admired Han's collection of David Hockney). It's a real home from home and it was hard for us to leave it behind.
Couldn't recommend more and hope to be back very soon!