The place is located a 15min walking from Oslo S. , really convenient place, you can travel around easy (Oslo is not so big anyway).
The apartment is really big and well equipped if you plan to cook, or just chill out (tv, radio, internet), so I totally recommend it if you travel with friends and need 2 separate rooms.
They where waiting for us to arrive, so check in went smooth, Internet didn't work when we arrive the first day, but they fixed it the next morning (fairly quick), communication was always quick.