We were two adults and three teenagers and Marius's house was a great place for us to stay. It was important that we all had private space as well as a good communal area and Marius's house really worked for us. Fantastic bathroom and private sitting room downstairs for the adults in our group!
The house is walking distance from the city centre and from the train - we had large wheelie bags and it was easy to reach from National Theatre train station. We spent a day walking round all the sights of Oslo and the house was not too far to walk home too even when we were tired. In a very quiet residential area but with small supermarkets and local restaurants very close by.
Marius was really easy to communicate with and sent prompt replies.
All in all we had a great stay and would recommend Marius's house.