The apartment is very nice and the position is great, you can easily reach every place of interest by walk.
I had just one problem: they forgot to tell me that I had to press a button before inserting the door code, and fortunately I met a person who live in the building who explained me how to do. In my turn, I helped a girl with the same problem some days after.
Apart from this (and apart from the kitchen poorly furnished) I think this is a great place to spend some days in Oslo, especially for the position.