We stayed two days at Hege's place. Hege is an extremely kind host who took time to talk with us and to give us a lot of advices on cool places, bars and restaurants to go to. We also talked about life is Oslo etc.
The flat offers a nice view over Oslo and the Fjord and is easily reached by bus from the city center.
I can only recommend Hege's place and would stay there again if I come back to Oslo !