Originally Posted by dukesilver
I'm currently reading dance with dragons, and when I select publisher font, the spacing between lines is too large. is that what the KF8 line-height bug is?
It doesn't matter if you're using publisher font or not (except 'Publisher Font' option is only available for some KF8 books). Line spacing is a little larger than with mobi, using the same Typeface and Spacing settings. (Though I'll say that in the case of DWD, I did look at a book sample and with the publisher font the spacing seemed too large at the Medium setting, but less so with regular/sans serif. But it may be just the font metrics rather than KF8 rendering per se)
It doesn't particularly bother me, and in fact I think it looks just fine with the font I typically use. But the problem is that when you switch between mobi and kf8, the appearance changes, which for typographically sensitive people can be annoying or distracting. Amazon would have done better to make sure the spacing remained the same, but I don't think we can assume that Amazon regards this as something they need to address in an update.
I would rather they offered finer-grained user control over line spacing (at least 5 settings instead of just the 3), and made text settings book-specific. Publishing guidelines advise against publishers mucking with the default line spacing, text size and typeface (when not embedding), and given the different screen resolutions, different built-in fonts on different devices, and now a variety of embedded fonts, there's no way for it to look equally good on all devices by default (typography is an art, and reasonable people will differ on what they think 'looks good'). For example, Sony PRS-T1 has a system-wide default, but it retains user's settings for each book (including Orientation). That works pretty well.
There are issues with specific books in KF8 format. For example "Wool Omnibus Edition" somehow has its font set about 3 notches smaller than normal. It looks fine on Fire, and in mobi. I don't know if this is an authoring issue or a bug with KT's KF8 rendering.