My shill for Apple here is that the simple sliding animation is much better. I never liked that book animation. It felt heavy and distracting and out of place like most skeuomorphism.
It wasn't just skeuomorphic, it had a functional component. It helped you keep your place and maintain context as you turned the page, just as you'd do with your finger while reading a real book.
No one has ever designed a physical book that works anything like the new page-turning approach, and you have to believe there's a reason for that.
