We like to think of what we're doing as Lean Publishing (self-published in-progress ebooks), not vanity publishing. We only earn money if the author does, unlike most of the scum that prey on authors who wish to self-publish and spend thousands of dollars to get a box of books that sit in their basement.
The Leanpub workflow is totally free to use, and we're making it better all the time.
Now, frankly, I'm a programming book author myself (I've written 3 programming books) and we have tons of programming books on Leanpub -- but I really wish we had a lot more romance and other "genre" books than we currently do. I even went to Brisbane to speak at GenreCon Australia (http://www.genrecon.com.au/) in 2013 to try to jump-start this, but frankly our usability wasn't there yet. We'll get there.