[Quoth]

Originally Posted by Hyphen-ated

yes, in KOReader you can definitely have subfolders and nest them as deeply as you want. so for example if you wanted a layout like genre/author/title.epub, you could do that.

And impossibly slow to browse.
It's a file browser, which only suits things with no metadata.

Originally Posted by Hyphen-ated

i'm not sure about having a book appear in multiple places though.

Only by having multiple copies

Originally Posted by Hyphen-ated

given how much faster KOReader turns pages on a Forma than Nickel does, i'd expect it to also be noticeably faster on a Sage. (although the cpu on a sage is quite a bit better, so maybe not)

Even page turn on Touch Version C and Original H2O is fast enough for epubs.

Originally Posted by Hyphen-ated

the behavior of the ui in KOReader is also much more customizable, like defining tap zones of whatever size you want, anywhere on the screen, to take whatever action you want

But the default My Books, + search + Built-in reader is sufficiently customisable. Really all the KOReader "features" are only needed for poor PDFs (which need a big screen) or bad epubs. It's really hard to remember where a setting is on KOReader. So I only use it on eInk Android now and only for epub. The eink Android's native PDF is easier to use. On regular Android I use Xodo for PDFs and images, mostly technical material. I use PocketBook for TTS and Lithium otherwise on Android, though I also use Borrowbox, GooglePlaybooks, Libby etc on eink and regular Android.

I'll only consider re-installing KOReader on any Kobo if it can have a UI as good as Kobo's to browse/find an ebook. I've tried KOReader's Calibre Metadata search and it doesn't mitigate the clunky File browser default.