Looking at this because we have never been on a cruise and I like the idea of it being AI and informal. I've always been put off cruises because of the impression of snobbish formality.
I have DS18 and 16 and lots of people have suggested that a cruise might suit teens. I would combine it with a week in a hotel.
Cruise reviews are tricky because they all seem to be written by the older clients who have been on hundreds of cruises.