We chose Cunard because it was named as a Northern Lights Cruise. We wanted to see Norway, Northern Lights and Viking Villages.
The Cunard transfers to get to the ship and back were seamless. Great flights, the shuttle service was on time and accommodating both directions. The ship onboard and offboard process was seamless and easy.
The cabin steward and purser staff were very helpful and friendly. The wait staff in the Brittania were subpar compared to other cruise ships. They learned our normal drink order habits but didn't learn our names or act at all friendly. They were very robotic. I think perhaps each waiter had too many tables.
We were in cabin which has a 3rd bed that pulls down from the ceiling. The mattress on that bed is very thin. If your 3rd person in the cabin is less that 5'7" I recommend they sleep on the couch which is far more comfortable. The back cushion are removable and the cabin steward will make it up as a bed for you. If you are going to be in the North sea and want to have the smoothest ride, this low cabin is a good idea. People from the Higher floors came down and slept on the sofas on the 3rd deck on one rocky night.
The Polar Park is a great excursion if you are able to walk a couple of miles on snowy roads. The wildlife and scenery are amazing. Remember that daylight hours are very limited in the winter and plan your time accordingly. If we had chosen the later of the two times we would have been walking in the dark.