[Turing_Machine]

However, Kindles can't read epub directly. If you're trying to produce a file you can sideload on your (or your customer's) Kindle without going through Amazon, you're still gonna need mobi, or one of the later proprietary (and undocumented) Amazon mobi variants.

[Finnucane]

True, but I wouldn't count on that being supported forever.

[Turing_Machine]

The day Kindles stop supporting side-loaded third-party content is the day I stop buying Kindles.