Safak and her collegue Ahmet (even German speaking!) were really nice and helpful and they were waiting for us in the apartment when we came. Also email contact in advance was very convenient and they answered always quickly. The apartment did have some lose ends: Doors, that couldn't be closed for example. We were 8 people and I wouldn't recommend it for more, since in one room the double bed was very small and in another the door could only be used when the bed was lifted up.
Since the apartment is in the groundfloor/basement, there were not many windows and the air wasn't always the freshest.
The location was perfect though, the area was quiet and we could walk everywhere.