Georg has been extremely welcoming and helpful with us, even if we didn't have the chance to meet him. He replied by email or sms straight after any sort of request or question we asked him while we stayed in his flat.
The flat is exactly as it looks in the pictures, it was very clean, quiet and warm. It is 10-15 minutes by walk to Marienplatz, near to the Underground and almost in front of the bus stop to reach the Central Station.
We would recommend it!