We had a great time at Ron's appartment. We only met him personally for a brief moment,but he gave all the info we needed, a contact person while he is out of town, and he stayed in touch to make sure everything is ok.
The appartment is very big and spacious, with a small balcony. The kitchen is equipped, the shower is good and there is a washing machine/dryer.
It is close to public transport (warschuer straße, close to kreuzberg and the east side gallery), has 2 supermarkets nearby, and is a few minutes walk from boxhagener platz - where you have almost unlimited choice of restaurants and bars. The berghain club is also only a few minutes away.
I would absolutely recommend staying there when in berlin! :)