The rule is #books are better than #movies based on them. I think they accomplish different things though: books have more detail, movies can show what you may have missed
While I think usually books are better, I have a theory that #childrensbooks DO adapt well. Simply, they have less material to adapt so they can add more depth to what is there. A great example is Wizard of Oz. I've read the book - it's good, not great. The movie is, especially for its time, amazing
Quotes that show #kidlit is not just for children:
“It was morning. Some of the sky was yellow, some the softest blue. One small cloud scuttled along. Strange how everything below can be such death and chaos and pain while above the sky is peace, sweet blue gentleness. I heard a shaman say once, the Ancestors want our souls to be like the blue sky.”
―Shannon Hale, Book of a Thousand Days.