Originally Posted by JSWolf
You would be limiting comparability tremendously as all stand alone readers are ePub and most apps are ePub. There really isn't ePub 3 yet.
I'm still in the learning stage on how to produce ebooks. I need to learn the structure, setup files, etc. and then write a program to convert my HTML-based stories automatically to ebooks. I thought by the time I start producing ebooks, ePub3 will be more widely accepted. That's why I want to start from the latest specifications. However, it appears from what you said that ePub3 won't be widely available for quite a while.