After booking Hendrik sent us an information folder with everything you could possibly need to know about the apartment and the neighbourhood. When we arrived Hendrik met us at the apartment with the parking ticket he had arranged for us in advance, explained everything and was eager to give tips about the environment (restaurants, outings and the like). Before, during and after the stay Hendrik was very easy to reach and willing to answer any questions we had.
The apartment is spacious and very clean, it has everything you could need for a short trip. There are a couple (couple years old) travel books about Berlin available in case you didn't bring one. The heating works very well, which is nice in the cold winter. The street and building are quiet so no disturbances at night. We were able to leave later in the afternoon, which Hendrik offered himself.
Prenzlauer Berg is a very nice neighbourhood with lots of restaurants, breakfast places, bars around. The Kulturbrauerei and Mauerpark are walking distance (15-20 minutes) and there is a big supermarket right across the street (open 07.00-23.00h).
All in all a very positive experience, we highly recommend this place.