I will only cover the areas where I feel I can add anything to the already comprehensive reviews of Norwegian Gem & the Transatlantic sailing Dec 07 (Barcelona to Boston).
Stateroom: Our stateroom, a mini-suite was very nice - well equipped with a fantastically comfortable bed but I'm glad it was just the two of us and we didn't need to use the sofa bed which would have made things very tight. Our cabin was always made up/turned down on time. The very shiny woodwork finish must make cleaning a nightmare and finger prints could still be seen even after cleaning.
The ship: She is fantastic - quite loud/garish dEcor but fun, in particular the beds in Bliss and Spinnaker lounge! It's all a matter of personal taste but we thought overall it worked well. We loved the four lane ten-pin bowling alley in Bliss. Also the stability of Gem was amazing, when we had one evening of slightly rough seas it was only in the corridors that the roll was very visible.