Originally Posted by tonyaldr
I have both a Nook Color and an iPad which allows me to read both Nook and Kindle editions. If one finds a book in both formats, is there an advantage to buying one over the other? I almost exclusively use my iPad which has both apps installed. Just wondering if one format gives a little extra over the other. I notice that this particular ebook is twice the price in the Nook format. Is that due to that format having some quality or feature advantages? Thanx!
Price differences - These are not the result of any difference in the formats themselves. They are primarily differences in the two stores and their marketing decisions. The differences in the DRM system used by Amazon/Kindle and almost all vendors of DRM bound ePubs do give Amazon some possible cost advantage. Amazon owns and manages their own DRM system. Most ePub vendors that use DRM use Adobe's system which adds the cost of the payments to Adobe.
Format issues discussed in this thread - You should ignore the issues that BookCat mentions unless you intend to buy an used older Sony ereader. BookCat's issues are not with ePub per se but are with the limited ability of the older ePub reading engine used in early model Sony ereaders. These issues don't exist with modern ereaders, either devices or apps.
Format issues worth of consideration - There are really three formats involved here; ePub, Classic Mobi, & Mobi/KF8. Classic Mobi (98-99% of the Kindle compatible ebooks as of this post) doesn't support some of the more elaborate formatting that is supported in ePub and the brand new KF8 format. Most fiction novels don't need any formatting control that is not available in Classic Mobi so for vast majority of readers these difference are not an issue.
The bottom line is that with a general purpose computer (e.g. tablet like the iPad) there is no need to be concerned. Load apps for both and collect books in whichever format you wish.