I have only been on one cruise and the wife has taken two. All were on Royal Caribbean. Her parents used to take a cruise a year for many years and have used most all the cruise lines. They prefer Royal Caribbean and Norwegian. I didn't particularly care for Royal Caribbean, too fancy for me. I'm a blue jeans and tee shirt kind of guy with a taste for real food. Fried chicken, meatloaf, mashed potatoes etc. Fancy does not impress me. The wife however likes to get dressed up and go out to eat to places that give you way too much silverware and small dish towels for napkins.
The cruise she is looking at is on Norwegian. I really don't know anything about them.
edit to add. One thing I omitted was a question about the food. From what I have been able to gather from reading online most of the best places to eat on the ship cost extra. Are cruises no longer all inclusive? The one cruise we took I don't remember having to pay for any food although I didn't get to eat in the main dining room due to a lack of what they termed proper attire. All I took was tee shirts and shorts and sneakers.