Having problems now with the way Amazon previews books on its 'Look Inside' feature. I've tried running ePub files through Sigil and other services but to no avail. Even though they look fine on all devices, they just look wrong on Look Inside. That's annoying as it's almost always the first time the customer will see the book.
Luckily, the next version of the writing software I use will soon be out so hopefully these issues will be dealt with.