One thing you should keep in mind is whether or not you want the ability to strip off the DRM in the future.
I and many others choose to buy formats whose DRM has been broken, so that if needed we can format shift our books to preserve our investment.
I'm not going into legalities here, but having had past bad experience with DRM, having this option is a Priority for me.
If so, the you format of Choice is probably going to be Mobi, eReader or Lit not ADE / ePUB as ADE's DRM has not been broken (Or stayed broken at least).
|