I stayed here for one night in September 2011.
The Holiday Inn City Centre is steps away from the railroad station and in the heart of the retail and restaurant area as well as convenient to the cultural buildings where concerts etc. take place.
Also, the Finnair bus to the airport loads 200 meters from the entrance to the hotel and takes you to the airport in 30 minutes for Euro 6.20.
The rooms and bathrooms are not large but quite adequate; nicely furnished and spotless.
Hotel staff speaks excellent English and are helpful giving directions to people not familiar with Helsinki.
There is access to the internet in the business facility and other conveniences for free.More