Amazon now sells more Kindle books than they do hard-copy books.
I just read my own book on a Kindle. I was not happy with the page layout, or the way my book read. (I read a lot of Kindle books.)
If I were writing the book today I would do a few things differently, to make the book easier to read on a Kindle. I would:
1. Use a simpler layout, with short paragraphs (130 to 200 words max).
2. Use extremely high contrast black and white illustrations.
3. Rely more on stories and anecdotes to illustrate concepts.
4. Use illustrations that stand alone, and don't have to be physically placed on the page close the text.
5. Limit or eliminate tables
6. Limit or eliminate numbered lists (The numbering scheme in my book did not translate to Kindle)
7. Limit or eliminate bulleted lists.
Maybe eBooks will one day faithfully reproduce the layout and contrast ratio of a printed page. But until that day, I'm going to use a much simpler layout on everything I write.