Not expecting to travel in the lap of luxury. I've done similar from Rostock and Karlshamn to Ventspils years gone by, generally the ferries were pretty basic, most of the traffic freight, with a self service type restuarant and lounge bar/snack bar. If you fancy a drink on departure it's a beer from a vending machine by the reception bit. Anyone expecting the sort of Pont Aven thing might be a bit let down.
Have booked a decent cabin so interested to see how that will work out.
Will report back..