Caveat: my son made me leave part way through the movie.
I did not want to see this. I love the cartoon. But, I was pleasantly surprised by what I did get to see. I will definitely make it a point of seeing the rest when it is on DVD.
My 8 year old doesn't love superhero movies (he doesn't ask to watch them) so I was surprised when he asked to see this. After about 20-30 mins he wanted to go home because nothing was happening. We stuck it out and he was so glad we did. He loved it (especially because there was swearing - his favourite thing).