This is an absolute gem of an apartment! I was born and raised in Oslo (Nordstrand area to be specific), and was travelling back with my wife and son, to visit friends and family.
If you're looking for something central, but not in the heard of downtown the location is excellent. Less than 5 minutes of walking to great grocery stores, coffee shops, bakery, restaurants etc., as well as public transportation that will take you straight downtown in 15-25 minutes.
The apartment was super clean and well equipped, just as described. Check-in instructions were very detailed and easy to follow, and Morten (our host) typically responded in less than 30 minutes if I had any questions. The only note I would make is, for anyone considering an extended stay, there is no washer and dryer so you would need to plan accordingly - not a negative, just something to think about and plan for.
Nordstrand as an area is excellent for families with younger children as the area is considered very safe, great neighborhoods to walk around in and tons of playgrounds. We would definitely consider this place for a future trip!