I spent a week at Oliver's place during a business trip, and here are my feedbacks:

The plus:
- A lot of flexibility regarding the time of arrival/departure
- A nice welcome and a willingness to make me feel at home (I even had my space in the fridge!)
- A very big room with lot of space and nice plants :)
- An overall clean apartment (mostly the bathroom, a real pleasure)
- A very central location (subway, restaurants, markets...) with a lot of animation
- Good recommendations about what to see in the area (access to local experiences I would not have known about otherwise)
- Oliver likes to share with his visitors but is at the same time very respectful of your space

The minus = your bedroom is otherwise the living room, which means:
- No double windows and as the localization is near a big road, it's quite noisy (but with earplugs it gets better)
- No curtains (but that's the case in a lot of places in Germany)
- Not a real bed but a mattress on a couch (too soft for me but once I put the mattress on the floor it was ok)

An overall good experience with a nice host in a living area!! If you're looking for a central place to stay with good advices to visit the city you can definitely come here!!