The location of Markus's place can't be beat. It is super close to the underground and in the middle of Kreuzberg. It's a bit noisy from the street, but if you're used to city noises it shouldn't be an issue.
The flat is a bit messy, it's a student flat, but the bedroom is clean.
My one issue with this place is the curtains in the bedroom. The bedroom shares a balcony with the bedroom next door, which is a wonderful feature, but the curtains are sheer. This results in a lack of privacy.