This is a great place to stay at. The apartment is very well situated; short walking distance to bus stops and subway station. The room is very cozy, clean and quiet. You'll have all you need for a pleasant stay in Oslo.
Mona is a great host and very welcoming. She will give you great advice on places to visit and is always available if you need something.
I wouldn't hesitate a second to book again if I'm back in Oslo!