I personally like the Australian one better.
I definitely don't like the US cover. Yuck!
I like the Aussie cover way better than the American one. I love the title font and all the bird flying around. It really reminds me of the Hitchcock film. On the US cover, those colors together are very displeasing to the eye. It's like an automatic turn off. It's a shame because book covers are so important. First impressions really do matter, especially in a book store setting.