June 10, 2011 6:23:47 AM PDT
Regarding the need for an ePub reader comparable to iBooks on MacOS X, I second that emotion. Currently, ePub is the only media type supported by the iTunes.app and iTunes U that cannot be "played" directly or indirectly (a la PDF) via the iTunes.app. That needs to change.
In the interim, one must sync to iBooks on iOS in order to get good feedback on one's writing. Perhaps iCloud will provide some relief but I really think that nothing less than an app will do. My MO requires rapid switching between the views of content creator and content consumer.
There is also the EPUBReader plug-in for Firefox, calibre and the Sigil and Adobe Digital Editions apps. Those alternatives don't yet support audio, video, etc. but the finalization of EPUB 3 should change that or at least I hope that it will.