5 of us stayed over the Christmas period and found the flat to be very spacious and stylish, however a little rough around the edges (very rustic!). the location is perfect as it is very close to U-bahn and bus routes into central Berlin. We got a taxi to the Reichstag one day that was no longer than a 10 minute drive. There is also lots of nice bars and restaurants near the flat.
A couple of things about the flat to note. There is only one bathroom which is very small and was unfortunately a little run down when we stayed. This was quite challenging for the 5 of us.
The flat is dimly lit with very few plug sockets which worked during our stay. The kitchen has basic cooking equipment (perfectly useable) which would be a little more tricky if you wanted to cook for a larger group.
Overall we had a pleasant stay.