"Save as eBook" is one of the most popular features (maybe even the most popular feature) of Atlantis Word Processor. But it has plenty more stuff to offer. In first place it is a word processor, not just a conversion tool.
I must admit that its features are under-documented. But you can find some info by exploring the following links:
http://www.atlantiswordprocessor.com.../atlantips.htm
http://www.atlantiswordprocessor.com...ick_tour_1.htm
http://www.atlantiswordprocessor.com/en/help