[eschwartz]

I would imagine the bigger problem is the inability to convert cleanly to EPUB, and being unable to feed AZW3 to kindlegen -- so why start with it if you don't need to?

I don't like editing AZW3 either -- because it requires decompiling and recompiling to open/save, I guess, whereas EPUB can simply be decompressed. But it is handy for touchups if it is the base format. Speaking purely as a consumer of the Kindle Store, of course.

That being said, I do like editing EPUBs, specifically in calibre editor. I was still new to the scene when it came out, so I tried both and stuck with calibre. I like the fact that it doesn't change even folder structure without being prompted, and I don't believe in WYSINWYW editing. But I wasn't used to Sigil beforehand, and calibre appealed to my inner geek.