Admittedly, it is a bit slow. It doesn't use text extraction, it uses k2pdfopt for reflow, which uses bitmap manipulation, and that requires a lot of processing power. As a result, it is supposed to better handle complicated layouts and be more true to the original. It will also work on scaned books. It does take 10 or so seconds to display the first page, and every change of parameters (F key) also causes it to freeze for 10 or so seconds, because the author decided to show the changes live, instead after you close the options menu, and every change needs the page to be processed again. That's why it is not good for browsing, too.
However, for actual reading, when you spend more than 20 seconds on page, the caching kicks in, and next pages are processed while you're reading the current one, so you won't notice freezes.
I'm not saying that Duokan is not better suited to your needs (especially if you read novels or similar not demanding layouts). I'm saying that kpdfviewer's reflow is quite usable (although a bit slow to start and configure).
Last edited by Kai771; 11-03-2012 at 08:32 PM.