The kids loved this movie. We have 3 - ages 7, 5 and nearly 3 - and they all throughly enjoyed it. They danced to the music and laughed at the cheap jokes. As soon as we left the theater, my 7 year old asked me when we could buy the DVD.
As an adult, it was tough to sit through. Even in kid movies I usually like to watch the whole film but this time I got up and went for the free refill on the popcorn. Twice.
I can't compare it to the first Chipmunks film as my 3 year old was only 1 then so I was out in the lobby for most of that movie. But I've never had an urge to go back and see what I missed so take that for what its worth. My guess is if you or your kids liked the first one, you'll love the second one too.