I stay there quite often, in fact every time I'm in Helsinki and I just love it! It really is an excellent hotel, both in terms of facilities (rooms, restaurants, health club) and service, which has always been impeccable. As a regular, they quite often upgrade me and the suites are really fantastic!
I highly recommend the Kamp to anyone travelling to Helsinki, and as sxchan wrote the rates are often a real bargain for a true luxury hotel.