Our family had cruised with Carnival before and moving to NCL was well worth the extra cost. My wife and I originally booked at mini-suite with the kids across the hall in an inside room. From them beginning of the cruise our balcony sliding door whistled anytime we were moving. We asked our cabin steward about it and he immediately had maintenance look at it. They said they fixed it but by that night it was whistling again. The next morning, after not much sleep, I went to guest services and they moved us to a balcony room, which was all they had available (a downgrade). They offered us $100 on board credit and a free dinner at Cagney's. Once off the ship Norwegian also gave us $600 toward a future cruise.
Overall the Gem was a great ship for our family. Even after my wife and I moved cabins our original cabin steward kept an eye on our teenage kids and made us feel okay being a deck away from them. Our teenage kids loved the activities and made a lot of new friends. Most of the teens on the ship were from NYC/NJ/LI and they has stay connected with many of them. My wife and I were always able to find some quiet places (not around the pool) to relax in the afternoons on the ship. I had the spa package and made regular use of the thermal chairs, whirlpool and sauna.
Food on the ship (buffet and main dining room) was much, much better than the food on Carnival. Our one meal at Cagney's was on par with many NYC steakhouses we have eaten at.
Went to Epcot with friends that met us at the port. Don't expect to spend a full day at any park. Enjoy what you can. If you want to go to Disney, make that your vacation destination.