I must admit I loved parts of this movie and other parts I hated; which is not to say they were bad, I simply didn't like some parts because of the emotions they brought to the surface. The voices is a very dark comedy; there were parts which were completely laugh out loud funny (eg: many of mister whiskers' lines) and other parts were tragically serious.
I am not a Ryan Reynolds fan (at all) but this could have changed my mind completely, I didn't realise that he had done the voices until I read about it here. Jackie Weaver was outstanding as the psychiatrist American accent and all.
What I found outstanding about this movie is that it has very few of the dumbed-down, pathetic and predictable traits of the trite drivel Hollywood peddle as "comedy". There was no comparison really.
I recommend this movie to anyone who enjoys a thought-provoking, less than predictable adult-oriented movie (ie: people who aren't offended by adult concepts and the f-word).