I spent several months last year researching how to produce an epub version of my textbook that I wrote with LaTeX. It's a book on programming in assembly language so has lots of math, code listings, and vector graphics. I came to the conclusion that I would have to "dumb down" the look of the equations, listings, and graphics to such a point that it meant essentially re-writing the book. I gave up and finally published it in pdf and paperback. I will say that LaTeX made it very easy for me to tailor the pdf version to ereaders by making small, uniform margins (no gutter), hyperlinked cross-references, and syntax coloring for code listings.
If I write another book, I will not use LaTeX. I love it, but there is no good path to epub. Since I have Office, I will probably just use Word.