The 3D effect was stunning and spectacular, and unlike most 3D films, did not frequently resort to cheesy tricks like having ball or pointy object come too far out of the screen.
The plot was not nearly up to the same level of polish as the visual effects, although it was a serviceable "noble savage" morality tale as long as you didn't think too hard about it. For example, in the beginning of the film brief mention made of the MacGuffin still has the screenwriter's placeholder text as a name.
Otherwise it was a mostly thin plot (the villians were unequivocally evil) that followed a "Dragonball" type arc of steady powerups for the hero and "fighting => friendship."