I'll be honest, I'm certainly not opposed to epub, but I don't see it as the ultimate solution to producing ebooks either. Actually, I think the problem has more to do with hardware than it does with software. The screens used to display ebooks are just too small.
If for example you are designing a book of poetry then you will have lines wrap because the screen is too small, and there isn't much you can do about it -- no matter what software you use. The current e-readers work fine for novels and similar types of books, but virtually any book that requires special formatting is going to be hampered by screen size limitations far more than they are by software limitations.
Once we have screens capable of displaying letter or A4 sized pages then I still doubt I will be demanding epub support, but instead will want PDF support. That's my 2 cents anyway.