US // UK
This is another series that is inexplicably aimed at different markets in the US and UK. In the US, it's rightfully YA, but over here in the UK, it's published as an adult series. The covers definitely reflect this, and I don't think the UK one does the book any favours.
I love all the US covers for this series. They're fun, colourful and eye-catching, and I'm so glad I bought those editions. I would most likely walk right past the UK cover, and wouldn't even give it a second glance. It amazes me how the same book can look so different!