After reading these posts I tried the Bookerly font. It's nice but to my eyes it doesn't look as good as GNU's FreeFonts, in particular FreeSerif. FreeSerif is big (over 10,000 glyphs) and causes hesitation when adjusting font size and weight, but page turn time is acceptable. The number of glyphs could be reduced with FontForge to delete unwanted languages but I never bothered.
http://www.gnu.org/software/freefont/