answer:To sync: no. iBooks will sync with ios devices, Kindle’s with their mobi files, but if you’re looking for a sync solution over all devices, that tech doesn’t exist yet. It would be super-cool, but it will probably never happen. (Amazon likes their proprietary formats, as does Apple.) However, as you said: ”...convert them to mobi files and use on the Kindle but that is a good bit of work” – download Calibre – It converts to all formats, and takes mere seconds. Hope that helps; others may have more to add, but I’m super-sleepy. You can PM me if you want and I can explain in more depth, but I think I covered it.