I always convert to epub format so that I can actually read the book as intended on my Sony reader. Of course this often requires first removing the DRM restriction so allowing me to use the book I have purchased. Actually removing the DRM is something I always do, even for books purchased in epub format. This is why I have been reluctant to purchase from Amazon recently, even if they offer a better price. It is my understanding that it is no longer possible to get rid of the new DRM they apply and this would make my purchase useless to me.