The rooms are decent size for Oslo, especially the apartments, with kitchenettes that include a fridge, stove, and sometimes a microwave. You can cook a real dinner here and eat it at a real table. For a city where a sad bowl of pasta costs 200 NOK, that matters.
The breakfast is great. A massive spread of local ingredients, smoothies, fresh bread, hot dishes. On weekends, though, the dining room gets slammed around 9:30 AM. Get down before 8:30 or prepare to stand in line.
Location is excellent and, more importantly, quiet. The Royal Palace park is across the street. National Theatre station, which connects to the airport express, is a five-minute walk. Karl Johans Gate is right there too. You get the central location without the central noise, at least from the street side.
From the back side, different story. At the time of writing, there´s active construction on a neighboring property, running 7 AM to 7 PM on weekdays. Rooms facing the inner courtyard or back street get hammered with drilling and machinery noise. Book a high floor facing the park. The walls inside are thin too, so hallway chatter and footsteps from upstairs will travel.
There's a free coffee machine in the lobby, cappuccinos and lattes around the clock. A guest laundry room on the first floor is available if you ask reception for a key. The gym is better equipped than most hotel fitness rooms in this price range.