Pass the popcorn

Last week my family was visiting my mom and since Grandma never gets to spoil the grandkids because she lives 3,000 miles away, the day with grandma included a trip to see a 3-D movie. Yep Grandma is secretly a 3-D fanatic. She even saw "Shark Boy and Lava Girl" (No grandkids were available to go with her so she took her long suffering spouse.)
Last week she had willing volunteers to see "Legend of the Guardians: The Owls of Ga'hoole" in 3-D.
Here is my breakdown of the experience. We went through 2 large popcorn tubs while we were there. Meaning either it was so exciting we kept reaching for the popcorn without realizing it or it was so boring there wasn't much else we could do. Both are true depending on who you ask.

I was enthralled and loved the colors and the animation. I think it was a beautifully done movie. My 4 year old got bored half way through and started running laps of the theatre when his popcorn ran out. Since no one else was in the our showing I didn't bother chasing him so I still enjoyed the film.

My mom thought it was "confusing." She felt several plot points were never explained. She chalked it up the fact that it's based on a book.
My 9 year old turned to me at the end of the film and said, "I bet the book is ten times better." So we went to the Library and got a copy and by Saturday afternoon he confirmed that the book was better from start to finish. He still enjoyed the movie though.
What's the verdict on the Owls of Ga'Hoole? Its worth seeing, but if you can read the book before you go, then it might make more sense. My warning is that the middle story building might get tedious for younger children although they will probably like the beginning and the end.
Any opinions on this one?