Tried this out, ligatures are nice and all, but I still went running back to RMSDK due to word/letter spacing.
My ideal epub reader would have the features of a modern web browser (HTML5 + CSS3), which I believe the Kepub render has, with the typography of TeX and its variants. Kerning, ligatures, Knuth & Plass (TeX) linebreaking, microtype (as used in pdfTeX and LuaTeX)? Yes please!
Unfortunately, no one seems willing or able to create such reading software
Typographically, RMSDK seems to be the best available software... just a shame about the lack of features.