I know about then; as they're a Norwegian company you'll get the best experience with them. Not mahoosive ships so easier to enamel/disembark. I would say they're the equivalent of a 4 star in terms of rating. I've been on a cruise to Norway with Fred Olsen, along with dh and dd age 2ish then......we had an absolute blast and loved Norway!
Major envy! I would go again in a flash. I hope you get to see the lights. I'm now drooling at all the lovely food we ate....a lot of it too. And the strawberry daiquiris we consumed - vast quantities also....! Im still trying to lose all the weight I gained; we went in 2006!!!!