The tough thing I noticed for the little ones was that several times during the show, the stage was vacant. Which was a bit of a magnate for all those budding Hannah Montanas. Once one kid got up there, they all wanted to be up there. That is until there is the announcement that says "for the safety of the performers, guests should remain off the stage" To say some of the kids were unhappy about that was a mild understatement. So dragged off by parents they were, until the next time the stage was empty and they were all up there again. Many tears and tantrums.
As someone else mentioned the show is quite long, and there are periods were nothing is going on, while you eat. Which is why the kids get bored and flock to the stage. I guess you know what you're kids boredom threshold is. My son was 7, and really loved it, we all did, it was a lot of fun. Not sure he would have been quite so good during the lulls in the show if he was a few years younger.