Been messing with KOReader the past few days, so have some more recent impressions:
Pros:
- You can override an ebook's settings and apply the same settings globally.
- Very fast rendering; page turns are instantaneous.
Cons:
- Interface is a nightmare; to get the exact look you want requires tweaking dozens of settings scattered across numerous nested menus, and to apply settings globally requires you to press and hold on each one and select it as default.
- Browsing by folder instead of tags is annoying, and I have found no way to view the collection simply as a list of books.
- Extremely slow to open and make changes to very large books, and complex formatting will simply cause KOReader to choke (I have an ESV Study Bible with tens of thousands of footnotes and links; opens in seconds with the stock Kobo reader; KOReader simply hangs and requires a device reboot).
So I stand by my original assessment that KOReader is for "power users" who like playing around with software while the stock reader is the "it just works" option for those who prefer to spend their time reading.