Doing some research and looking at this Cruise Critic site gives nobody any single excuse for complaining about Norwegian Gem. Everything you need to know has been said by others.
Info: I'm just back from a week in the Western Med with my wife and three teenage sons. (17.14,14) Activities: Plenty. From the rock wall, the pool, the sports pitch to bingo. I wouldn't see my kids for hours. They loved the ship.
Service: Much is said that the service is not up to scratch because tips are "included" in your on-board account, meaning that the staff do not have to make any great effort to secure them. That idea is rubbish. They will all do all that they can to make your trip a good one.