We love cruising! Just got married on a cruise ship in August
We are looking at a 8 day for Fall 2018.
I know Carnival gets a bad rap, but honestly we really enjoy their ships. I've been on about every class and have had a blast on all of them. I think it really depends on the time of year and length of cruise. Short 3-4 day cruises, especially around spring break, will probably yield a lot of college kids, young adults, party atmosphere, etc. Longer cruises tend to bring out the families and older crowd. Always had great experiences with food, drinks, entertainment, ports, etc. No experience with kids clubs, but have always heard good things. Newer ships have water parks, mini golf courses, huge outdoor movie screens, kids/teens only areas, etc.
I've cruised RCL once before and would be more than willing to give them another try. I hear such mixed reviews on their mega ships. I think you love them or hate them. To some, they are completely overwhelming and fact you have to make reservations for dining, shows, etc. turns a lot of people off. (Makes me think of Disney & FP!) But if you had kids, having a newer ship with SOOO many things to do would be a plus I would think.
NCL has never interested me and I can't think of a rational reason why. I'd like to try all cruise lines and NCL seems comparable to Carnival in terms of price.
I'd LOVE to do Disney, but good lord the price just scares the heck out of me. We don't have kids and it's just hard to justify. It would definitely be a cruise we'd budget for a few years in advance and just do it. I'd love to do the British Isles itinerary if they keep that one around.
Whatever cruise line you decide to go with, I would probably recommend a newer ship for a family. There's just more to do and you can decide what you like/dislike. If you go on an older, smaller ship, you might feel like you're missing out. Spring break time is peak and will come with higher prices. It might be fun for you to look at the dates you can go, see what's available in your price range, then go through them with your family and see what they think. I like VacationstoGo.com when I first start researching. You can search by ship, cruiseline, dates, departure port, etc.