Very funny, achingly tender and sad, just brilliant.
It's great to see a kids film that doesn't have loads of sub-Shrek jokes and references for the adults all over it as well.
Rollicks along at a wonderful pace, and when it gets sad I don't think it does it too heavily or in a way that would fly completely over the kids heads.

Easily one of the top five films i've seen this year, and the accompanying short is one of the better ones too.