I don't usually comment, but after reading 362 messages in this thread over the course of a few hours I felt compelled to offer my opinion.
I think it is great that Sony is going to epub + ADE. No, I don't like DRM, but at least it is more portable and I can always strip the DRM if necessary. Even if Adobe goes out of business there are several bookstores using the format and I'm sure that at least a few would continue to do so for at least a while afterwords.
In reference to ahi's many posts, I know PDF is great for formatting for a specific document size and it will look the same on any device that looks at it, but I seriously doubt they will modify it to contain multiple sizes with multiple fonts for you to download to any ereader. And if they did I can imagine that even a properly formatted PDF would be a very unreasonable size by the time you have accounted for 6 screen sizes and 6 font sizes, you would have 36 or more versions in every PDF.
I am a programmer and I have created a few mobipocket and epub books. I have become a bit familiar with typography because of this. The biggest drawback for Adobe's epub in general is the inability to support soft-hyphens in a consistent manner. See http://www.mobileread.com/forums/showthread.php?t=28139
I don't think you want the ereader to have to perform the task of auto-hyphenation, not because it can't be done, but considering the low processing power of such devices, it is impractical. It would be better for the publisher to go through and pre-process the document and mark any words that can be reasonably hyphenated with the soft-hyphens.
Not every book can be properly rendered in epub and maintain the author's original vision. But for any book that consists of only text and only a few different fonts it can be made indistinguishable from the original except that it is reflowable. Again, how it is rendered is dependent on the epub viewer implementation. The biggest problem with mobipocket, which uses a subset of epub, was that you could not flow text around a graphic. epub supports this and increases the number of books that can be reproduced in a reasonable facsimile of the original printed book.
Textbooks are still the hardest things to produce in epub and for the near future will almost certainly need to remain in PDF format. Using ebooks for textbooks brings in a whole different set of problems since they are not necessarily read linearly. The ereader would need to allow for some sort of tabbed bookmarking so that you can switch to different parts easily and quickly. They also need to have an easy interface for making notes on the document, be it a keyboard or stylus. However I think the epub standard and typography will change enough to overlap and allow for reasonable reproduction of textbooks.
While on the subject of PDF, I've seen at least a few PDFs from Google's book scanning project. Although the results look good, the underlying text that you can't see contains many typographic errors that may prevent you from searching the document or using a dictionary in your ereader. I'm sure that ahi wouldn't allow such bad workmanship to pass without correction though.
b0ned0me showed an excellent example of a bible that would be hard to do in epub format. I'm not sure how well text reflow is when it is boxed in like that. I would need to study the epub format a bit more, but I suspect that it is either possible or could be made possible. It would be easier if not every page was like these two though.
How good or bad the epub is, in the end, relies upon the same thing a printed edition would: the typography, proofreading and editing. epub does not eliminate the need for any of this, it merely changes how it is done. It is no different than when linotype machines ceased being used and they started using computers. Any unillustrated book that was produced on a linotype can be reproduced with equal or better formatting in epub.
I'm sure ahi would disagree with this, but I would like him to show an example of what he is talking about. Don't just say I'm wrong, back it up. As an example of what I'm talking about look at my post for Gogol, Nikolai: The Mantle and Other stories
and compare that to the PDF located at The Internet Archive
. The only problem with my copy is the lack of soft-hyphens. Plus it would be handy to have publishing software that would assist in the pre-processing.
I currently have a Kindle 2. I'm now considering buying a prs600, but I wonder if Sony will come out with a large format ereader which can make use of those PDFs.
After all they do work better for textbooks.