The apartment is really beautiful - very clean, stylish and well-equipped. The sofa and the bed are both stupidly comfortable and the terrace is wonderful. I only had one day of great weather during my trip but it was lovely to sit outside and have a coffee with a view over the water, and even if it's raining the big windows let in a huge amount of light and a great view so you don't feel like you're trapped inside.
The communication was excellent, and I got clear answers to my questions very quickly. Checkin is easy at the pub downstairs, and I was able to leave my bag there on the last day so I could wander around Oslo for a bit before my afternoon flight. There are also lots of tips in the apartment about where to visit.
The apartment is located a little far out from the centre, but it's an easy (and picturesque!) 15-minute walk along a bridge across the water, and there's a pub, a restaurant and a supermarket right downstairs so all the basics are covered. Besides, I doubt it's possible to find somewhere this nice for less any closer to the centre!
I highly recommend this apartment, and I will definitely choose to stay here again next time I stay in Oslo!