There a many different Hotel Thons in Oslo so please make sure that you book the right one. I actually didn't end up at the one I expected (Hotel Thon Opera which is the one that is visible from the Central train station), but fortunately I ended up at the Hotel Thon Terminus across the street.

Hotel Thon Terminus is a nice functional hotel that is well located in central Oslo. Free WiFi and buffet breakfast.

Rooms are small, but functional. Clean. Tiny bathroom for one (like on a ship), but the foor was heated - very nice in December when I was there. One twin bed that was a bit too soft for my liking. Not cheap, but most alternatives in Oslo are just as/more expensive, so it does offer decent relative value in this expensive city.

Thought we booked a queen bed and got a small twin bed. First room, the a/c did not work. talked to the front desk and was immediately moved to another room. Good breakfast, Lots of choices. Very helpful people.

We stayed at this hotel June 20 to 27, 2011. Aware of the street noise, we had a nice, quiet room on the 6th floor overlooking the breakfast room. The location could not be better any better. Minutes from Central Station, close the central bus station, short walk to Opera, close to downtown... The hotel was very clean and almost all the staff was very pleasant, helpful, and accommodating. They offer coffee/tea all day long in their reception area. Free Wi-Fi in rooms and a computer in the lobby for guests to use. Unfortunately, they don't do the dinner buffet I read about in some reviews during the summer months, but the breakfast they served was really good and saved us a lot of money. The only bad experience we had was the day before we checked out. We had to be at the airport by 7:00 a.m. and asked if there was any chance of getting something (anything) either the day/night before or around 6:00 a.m. when we had to check out. The answer was flat “no”. Was it because it was the receptionist we were not that fond of, or the hotel policy? Not sure. But it was pretty upsetting at 6:00 a.m. seeing the 150 NOK (about $50) charge added to our bill for a breakfast that started at 7:00, so we could not possibly have any of it. That was the only thing that ticked us off. Other than that, really good experience.

Rooms modern and well equipped. Everything clean and comfortable. Breakfast buffet extensive range of hot and cold food. Good location near transport, but on shabbier side of town.