We enjoyed our stay at Jan-Erik's nice appartment. We were four adults and it is perfectly suited for two couples. Very good situation, 2 min walk to the train/bus/ tram station, very quite neighbourhood.
All the indications before our arrival were very clear and answers to our question very quick. We just were a little bit lost to find the right 7/11 to take the key, but people in Norway are very friendly and we were helped to find the right kiosk.
We would definitely recommend this place if you come to Oslo.