I have been on 5 cruises previously with 4 different cruiselines (including Disney, Princess, and Royal Carribean). My experience on Norwegian Gem was by far the worst.
1. The stateroom is poorly designed, with no outlets near the head of the bed. Family members with CPAP machines had to run extension cords across the entire room to be able to use their medical device.
2. Stateroom did not seem fully stocked. I found out halfway through the cruise that hand/body lotion is readily available but was never stocked in my room for no clear reason.
3. The food was one of the biggest disappointments. Many dishes came out cold, and the portions for the appetizers are laughable. The food taste was mediocre at best. In particular, the quality of the food at Orchid Garden is not tasty at all. The buffet has poor variety. Despite having a large space, each food station is duplicated, so there is really only half the selection. And attempts at cost-saving were obvious... other cruises have smoked salmon, and this cruise had salmon spread. The tikka masala was always some vegetable rather than chicken. Just a few examples.
4. Having to tender to ports is terrible, and I left with the sense that my cruise experience was diminished due to cost-saving decisions by the cruiseline. 2 ports were cancelled due to weather preventing safe use of tender boats, but other cruise boats were able to dock at those ports on the same day as their cruiselines booked the pier rather than resorting to using tender boats. At one of the ports we actually made it to, delays in the tendering process led to our group having to wait 3.5 hours after our arrival time to actually make it onto a tender boat, so the time available to actually enjoy the port was lessened.
5. When ports were canceled due to weather, the cruise staff revised the activity options. But all I could see were more sales and charged activities (wine/whisky tastings). It's bad enough to miss out on a port, but then to have the cruiseline only open up activities that you have to pay more for is ridiculous.
6. My cruise benefit was to save $50 per port on shore excursions, and I was unable to use that benefit as half the ports were canceled. I had unused "non-refundable" credit that I asked be applied to the service charge since I was unable to use it on a shore excursion, and I was told that wasn't allowed. If a port is canceled, I would hope the cruiseline would go out of their way to try and improve the experience rather than make it more frustrating.
7. The cruise staff was overall friendly but one staff member (female cruise staff member from USA) was rude. She was managing elevator use while it was restricted for 4 hours due to tender boats.
8. The layout of the boat is poorly planned. With disabled members in our party, it was frustrating to have to take elevators up to a certain floor to walk across the boat and then take another elevator down to get to the main dining hall (which is a location we needed to get to 1-2x every day).
Great port but lost time due to slow tender boat process.
Beautiful drive around lake