We stayed at Sigvart's apartment for 3 nights during our visit to Oslo - and it really was a fantastic place to stay. The apartment is in a fairly new building, very clean and modern - ideal for 2 people. The location is great - it's located in an area that has been redeveloped. What was previously an industrial area is now a trendy mix of apartments, restaurants and bars - literally steps from the apartment. Even though there is a lot of activity nearby - the apartment is quiet, noise was never an issue.
When we arrived in Oslo we followed Sigvart's instructions to use the bus to get to the apartment - which was easy from the central train station - less than 10 minutes. It's about a 15/20 minute walk to central Oslo, which is a very walkable city.
While we never met Sigvart, communication via e-mail was always good and prompt. The pre-arrival information was clear and helpful.
The only criticism I can think of is that the roller-blind in the bedroom (floor to ceiling window) is about a foot too short. This allowed a fair amount of light into the bedroom - particularly when the sun rises at 4.30am!
Overall, this apartment was a great experience and we'd be very happy to stay here again if we return to Oslo.