DreamWorks has completely outdone itself with this production. The animation is spectacular, the story is both entertaining and inspiring, and and the characters/acting are superb. We took our 8yo to see the Rise of the Guardians 3D, and he loved it. The parents loved it, too -- Rise of the Guardians has as much appeal for adults as it does for children.
The only down side was the 'weak' 3D effects. The effects were there, but not by much; it was more 2.5D. On the positive side, we agreed that the movie was so spectacular that it didn't need 3D.
We will likely see Rise of the Guardians again before it leaves the theater, and will definitely be purchasing it when it comes out on BD.