It might still make a difference on how you transfer the book to the Kindle. I had trouble earlier on when I tried side loading kf8 books to Kindles and other devices with the Kindle apps. Sometimes they were viewed as kf8 books, often they were not. I have much better luck transferring kf8 books via Send to Kindle which uses the Kindle Cloud.

Another oddity is how various Kindles and devices interpret embedded fonts. Each seems to do its own thing and the results vary between devices. For example, the embedded fonts are currently broken on the latest Kindle for iPad app, work very well on the Fire HD, and works so so on the Kindle Touch.