I thoroughly enjoyed this film, as did my kids (8 and 3). The environmental message is very clear, and done in a beautiful and engaging way. The animation is absolutely stunning, the Strange World is fantastically beautiful.
While it was uplifting to see the connection between generations, I thought there was too much adult dialogue that went completely over my kids' heads and they found boring. It was a bit more serious than the character and set design let on.
Fortunately the dramatic action sequences, light comedy and stunning visuals kept my kids engaged.
Definitely a progressive film, if you're left leaning you'll probably like it. I can imagine more conservative people wouldn't enjoy it.