Just got back from Berlin, we (3 grown siblings) stayed 3 nights at the Prenzlauer apartment.

Positives:
- Great apartment, clean and very nice
- Well equipped (kitchen, towels/bathroom, rooms)
- Great location, once you move past the not yet renovated yard you are right onto Kastanjealle with all its restaurants and coffee places, shops and nightlife.
- Björn. Well we never met Björn as we arrived late so instead we picked up the keys at the Zaza bar that is located on the front of the house. We mailed Björn about late departure and as the apartment wasn't rented out the next day Björn said we could keep the apartment until 16 instead of 12 which we really appreciated!

Negatives (hard to come up with but ...)
- No scissors in kitchen :)
- The whole building is rough on the outside including internal courtyards (not a problem for us but maybe someone else)
- I slept on the sofa bed (unlucky lottery with other guests) and as most sofa beds it was not the most comfortable sleeping arrangement

Summary:

YES I would go back
YES I would recommend Björn & Zaza apartments
YES I hope to bring my girlfriend and 6 year old and stay at the same place next time I visit Berlin