ZReader is their second ebook reader/parser engine, that honors more of an epubs (html based) formatting (as in all of it, even margins), than their default reader (which strips pretty much all formatting out, only keeps paragraphs and headers, moves first lines inwards, and allows you to reformat text layout from there).
ZReader also is the only one of the two that can handle soft hyphens. (Yay!)
With the update, there now is a toggle to set this reader engine as the global default. (Go to the library tab, click on the three lines (top right), and its the last option (Reader settings). This will apply to new books added only. Older books still have to be toggled by hand (in settings in the individual book) as far as I have seen. (Or at least their older toggle value (if set?) overrides the global setting (which is good).)
Also in ZReader its now possible to adjust top and bottom margin settings. those are the new additions I remember (and have found) from the update readme screen.
edit: Also ZReader has a new default font (serif) thats actually very good (times new roman style - but thinner). Try it.