$310 sounds a bit like extortion. Based on pictures from this "cruise ship" you could make more than one "Day in Stockholm/Helsinki" cruises departing either from Helsinki or Stockholm in economy. I also think that those cruise ferries economy class provides more comfortable stay. Downside ofcourse that only breakfast is included in price.
I'm sure this "cruise" is a bit more exotic option but someone still needs 9mm pistol to "persuade" me to attend.
