Ninna was very kind and always reachable. The room is just as you see in the pictures and everything was super clean. The location is very convenient in between the center (Christiania 1 subway station away, and the center 2 subway stations away). Plenty of cafes, bars, restaurants and 2 supermarkets around the corner. The room was nice and clean. You have to go up 6 floors and then 1 extra floor up to reach the room, as long as you know this in advance should be all fine.
The only thing was that one of the 2 mattresses was "not in perfect shape anymore", resulting a not confortable sleep at all for me (my girlfriend who slept in the other bed had no problem). I guess a new mattress would solve the thing :)
Beside from this everything great.