You have to really love Disney or have kids who really love Disney to take and love a Disney cruise. My kids and I love Disney, my DH not so much
Disney is great at a lot of things especially service and entertainment.
Make no mistake - there are tons of kids on a Disney cruise - not all are well behaved - or have parents who care that their children are well behaved. I'm fortunate that my kids are in the well behaved camp so I focus my attention on the fact that my kids are enjoying themselves.
Now to answer your question. We had an amazing time on FOTS - but it was before our very first cruise. The character meets are not as obtrusive as they are on Disney. On Disney, we found ourselves planning our entire day around character meets and princess gatherings (our fault). My only complaint about character meets on FOTS is that a child could be lining up to meet shrek and stand in line forever, and then just as the child gets to the front of the line - they pull a switch a new character is subbed in - happened to us twice - both times with puss n boots - who my son was terrified of. That would never happen on Disney. They cut off the line and tell everyone new joining that line if a character change is going to appear, so you know upfront if there will be a character change. Disney also does a better job of catering to food allergies (my son is peanut allergic). Royal does a horrible job of that. By catering, I mean conveying what items contain nuts. Royal's policy is "if in doubt - don't eat it". Front-line workers don't even know what has nuts or doesn't. Disney also does a better job of managing the guest relationship/experience across multiple venues.
That being said, we love Royal, and the dreamworks experience, makes it a happy one for our family. My kids love the splash zone ~ and as they get older, they will be able to enjoy flowrider, zip, and other stuff. Though, nothing beats the AQUADUCK! Royal also has casinos - and my husband I both like to gamble. Loved both Fantasy and Dream - but like I said, you have to really love Disney to enjoy and get the most out of a Disney cruise. I doubt we will ever do another Disney cruise, but we'll see.
now back to your regularly scheduled discussion of dresscodes, jeans, fangs, and vampires