We had a wonderful stay at this apartment.
It has all amenities you need if traveling with kids - ours had a blast with all “new” toys and books. Wifi was great, nice bathtub (rare in Oslo!) and comfy beds. Everything was super clean.
Location is very convenient - close to “hippie” Grünerløkka but also to the city center. And if you do not wish to explore the city - the neighbourhood is super family friendly and has a lot to offer in terms of coffee places, food, playgrounds etc.
Highly recommended!