We spent 5 nights at the Radisson Blu Royal. We were upgraded to a business class room. The room could have used some renovation, but was overall quite comfortable with an espresso machine and free wi-fi. The staff was very helpful, and the included buffet breakfast was quite good although always very crowded. The staff did a great job replenishing the food and removing used dishes. We had dinner at the hotel restaurant and it was excellent and seemed to be patronized by a lot of the local people.
The hotel is very conveniently located with a tram/subway stop a block away. The T3 tram allows you to be anywhere in the downtown area in minutes and runs every few minutes during the day. You can get a multi-day pass for the subways/trams in the subway station. I believe we got a 4 day unlimited use passes for all the buses, trams, and subways for 2 people for 32 Euro. Helsinki was a wonderful place to visit and was our favorite of all the Scandinavian capitols. We also had dinner at the Hotel Glo’s restaurant and thought it was terrible with some of the worst service ever, the hotel itself also did not impress.
You can get some fantastic advance purchase rates from Radisson. We paid 78 euro inc Breakfast.