Although Tim wasn't there during our stay, his room mate, Fred, hosted us and made everything easy and pleasant.
The room is huge, with a really nice balcony and views. Furthermore, the area where it is located is great: lots of restaurants, a cool and multicultural atmosphere, and very well communicated with the downtown area by u-bahn and s-bahn (metro and tram). Fred even lent us a bike, so we could ride along Berlin's streets (which is absolutely adviceable!).
Regarding the check-out, we were able to leave the luggage at home, visit the city, and then come back to pick it up and go to the airport.
There were some noisy neighbours a couple of mornings, but it was nothing compared to the great things this place has! To sum up, the experience was great and the host was also very kind. I'd definitely recommend it!