We stayed in Orjan's apartment for 11 nights. We loved that apartment. It is quiet, perfect size with all the things you need, clean and close to Carl Berners Plass with easy connections to Oslo Center and other areas.
Orjan was the PERFECT host. He solved quite fast one problem we found in our fast day which is very important to feel safe there. He is a very nice and kind person.
Finally, the neighbours are very nice people. All of them are nice and kind people and you can speak with them and ask them if you need.
In summary, I recommend the Orjan's apartment if you are planning to stay in Oslo.