I think Katja's room is suitable for one person or a couple, for a short stay in Berlin. The bed is not very confortable but the room was clean and organized. It was a bit hot and by opening the window we had a few bugs coming inside.
The house wi-fi was not working but the hosts shared their mobile phones wi-fi with us so we do some urgent contacts.
The kitchen (even we didn't used too much) and the toilet served all our needs.
The house is not close to the center but it's in a very quiet and pleasent neighbourhood with restaurants, shops, parks and transports nearby. I believe this a very nice area to live in Berlin. We walked to the center but it was though and we got transport on the way back home.