As this is an Oxford dictionary, I expected this to be an 'English' dictionary and so was dissapointed to see the odd Americian spelling, such as realized. That being said, I think that it does give great examples for using the words in a way that children can understand.
I am also dissapointed that not all words are in the dictionary. Whilst that's to be expected, words such as landfill and organic weren't in there and given that kids are learning about those sorts of things these days (my 7 year old is!) then I did expect them to be in the dictionary.