Nothing is perfect, however. I've encountered a few bits of KDP weirdness that I should tell you about.
After uploading your interior file, Amazon offers a nifty previewer that lets you view your book on a simulated Kindle e-reader. You can switch from portrait to horizontal views, and also view other simulated reading devices such as iPad and iPhone.
[above] However, the preview may show some strange white blotches where text should be. I don't know why this happens, and the text gaps on the previews don't happen in the real e-books.
The other problem is equally disconcerting, and may be more damaging.
[above] The online preview on Amazon.com may show oversize type and even wrong color type. I've found this in three of my books. Strangely, the actual downloaded books are fine (at least as I've viewed them). However, a crappy preview may stop people from ordering your book, so it's important to fix the preview.
[above] The secret to making the repair is in the Outline view in Microsoft Word. The circular symbols to the left of your text actually mean something, and should not be ignored.
[above] This handy cheat sheet from the University of Wisconsin explains the symbols and what you can do about them. Simply highlight a paragraph that's to the right of a plus or minus symbol within a circle (indicating that it will be displayed as a header instead of normal text), then click on the double-right-arrow symbol at the top of your screen to change from a header to Body Text and save your file and upload again.
This procedure may take a long time with a big book, but it's worth the effort.
Now I'm going to add this material to my book, and go back to bed.