Gerhard's apartment is in a lovely and quiet Berlin neighborhood with good bus and sbahn access to the city center and tourist attractions. Gerhard is a kind and attentive host. He met me at the train station and walked with me to the apartment to show me everything. He was quick to respond to questions and was full of local tips.
The only con was you can only take a quick 5 min shower before the water gets cold. This is okay on a day to day basis, but disappointing after a tiring day of sightseeing.