I noticed the ghosting right off, though it wasn't severe. Setting the Refresh level to Every Page Turn pretty much cured it, without affecting the speed of the page turn. Which I've found in general to be very fast -- considerably less than a second -- though once in a while I get a much slower page turn.
I put on a ton of books (everything I had on the K3), and didn't find that the indexing time made a noticeable difference to the speed of the page turn. Sadly, it sounds to me as though your unit may be somewhat defective.