This is probably a hard question to answer. I've only been on Royal Caribbean, so I can't speak of how they compare to other major cruise lines. However, from what I have heard, their kids program is pretty good, and I've found the food to be good as well.
It really depends on what you're looking for, and what your budget is. Going back to the kids' program on Royal Caribbean, I read somewhere on one review that when the parents went to go get their kids from the program, the kids kept telling the parents "just a little bit longer." This to me seems that they are enjoying themselves in the kids program, and didn't want to leave. I don't have kids, so I can't speak first hand. I'm just going on what I've heard.
I kind of like what you're doing so far. Try different cruise lines and see which one out of the ones you've tried you like the best. I keep wanting to do a Carnival cruise, so I have something to compare Royal Caribbean to. Maybe if your budget allows, maybe try Royal Caribbean for your next cruise.
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas