We – two colleagues-friends – stayed in Siw's apartment for four nights during a conference. Siw was really nice, and everything went smoothly from booking to the day of arrival to the final day.
The place is exactly as described and was fully equipped for everything we needed, clean, and easily accessible from Oslo's train station by bus (2 minutes walking from the nearest bus stop) or tram (5 minutes walking). We enjoyed the common space with the open kitchen and living room on the upper floor to chat during the day while each of us had our own room downstairs.
Happy to come back when I/we return to Oslo in the future!