I took my 5yo son to see this yesterday and he quite enjoyed it. There was quite a lot of slapstick humour and interesting animation in it which helped hold his attention. Some of the Jim Carrey banter-type humour probably went over his head and would have appealed more to an older child. As for me, it certainly wasn't the worst kids movie I have sat through. Also interesting as I know Theodore Giesel/Dr Seuss was a political cartoonist as well as a children's book writer/illustrator (see here for some examples of his political cartoons).
I suspected when I read the book to my son that there was a political subtext in it, ie, possibly about the Cold War and McCarthyism (American history not really my strong point). The thing that triggered this line of thinking was probably that the vulture (or whatever kind of bird it was) was called Vlad Vladikoff. Also wondered about the monkey being called the Wickersham brothers (didn't seem like a particularly Seussical name).
Interestingly, just had a look for some explanation of the political sub-text behind the story and found this article:
http://www.latimes.com/entertainment/news/movies/la-ca-horton16mar16,1,3603666.story
"A person's a person, no matter how small," the empathetic elephant continually insists as he soldiers on his adventure. Pro-life activists have long attempted to co-opt this message, however the late epochal children's author Dr. Seuss -- né Theodor Seuss Geisel -- denied any political subtext to the line. However, a week after this interview, at the movie's Hollywood premiere, a group of demonstrators reportedly infiltrated the screening, chanting anti-abortion slogans and eliciting reactions from the audience such as "This is a kids' premiere!" and "How dare you!"
I actually thought that in Cold War terms, the residents of Who-ville might have been representative of the Russians behind their Iron Curtain and the kangaroo Joe McCarthy? This is kind of diluted in the movie though. I am guessing this is largely because of length (ie, film-makers having to expand a 20 page picture book into a 90 minute film so needed to introduce a whole lot of sub-plots and other extra details) but also because the film-makers may not have agreed with this interpretation or wanted to modernise it. Was interesting trying to work out what the film-maker's sub-text meant to be, ie, was the situation on Who-ville analagous to our world and climate change? Or was it about religious faith, ie, the mayor encouraging everyone to BELIEVE that the great elephant in the sky would help them? Or was it about free speech and repression, ie, Horton being hunted down and persecuted for expressing an unpopular belief? Or maybe it is all just a dogs breakfast and doesn't really have a consistent sub-text at all?
Interested to hear from anyone else who has seen this film and has some ideas on what it is meant to be about. While I am interested in American political history, it is not something I know a huge amount about.