I was in Oslo for 6 days for a conference. This was ideal place to stay -- walking distance to the city centre and with lots of public transport options (train, tram, buses, ferry) all nearby. Also supermarkets and cafes in close proximity.
The apartment itself is also amazing -- light and airy and with a great balcony with a nice view over the rooftops of Oslo. Apartment has everything you need for a comfortable stay -- including a small but well equipped kitchen -- and has a large living space to hang out in.
Gunnar made sure everything with checking in and out went very smoothly. I would certainly stay here again if I was back in Oslo.