I watched this with my family last week. My son (10) and older daughter (10) both loved the story and characters and my younger daughter (5) was entertained by all the cute animals and creatures, especially Splat.
The story was a bit predictable for an adult, but my kids found it highly engaging and they're the ones it's intended for. The animation was superb, and the voice acting was consistently good from the leads to minor comedy relief characters.
What made this film most enjoyable for me though was how much of myself and my family I was able to see in a variety of characters.