The e-ink display on the Kindle flashes black when you are changing pages and takes about a second to 'turn' the page. This forces you out of the imaginary realm of what you are reading into the real world.When you actually sit down and try to read on the Kindle (or Sony eBook) - you are constantly shoved out of your imagination by the lag and the full-screen black flash.Many have commented on the limitations of formatting and content. I have a simpler complaint - I can't get lost in a book in this format. The Black Flash kills the continuity.