There are a couple of things you will find different; as for packing, remember NCL is known for freestyle dining and sailing period. This means you will not have regular table mates, but can eat almost anywhere and anytime you want with several dining options. I don't know what ship you are thinking of sailing. The newer ones that went into the water in the past 5 years will offer about 8-10 dining choices with 3 or 4 having extra charges of $12.50 to about $20.00. You do not have to eat in any of them, most want to try at least one, but don't feel obligated. I do recommend, if you do want to try only one you make reservations for Le Bistro.
As for packing, again freestyle means there are no absolute formal nights; this gives you the option of dressing to the nines or keeping it simple. You will see, on the 2 formal optional nighs about 25% dressed in tuxes or dark suits for the guys and after 5 dresses for the ladies. About 40% will be in nice sun dresses with the guys in sports jackets or just nice sport or dress shirts with or without a tie; the other 25% will chose capris or nice pants and the men will be contenct in polo type shirts and slacks. Like all lines, leave the jeans at home if you think you would like to wear them to dinner. With the exception, pretty much of the Dream they still are not allowed in the dining room for dinner. No tank tops, no questionable T shirts but most anything else will work. Hope this helps a little. NMnita