[mobama]

For epubs on e-ink devices, Coolreader beats Koreader because in Coolreader you can configure tap areas more extensively. But my e-library overwhelmingly consists of pdf's and djvu's, so I am lucky to have Koreader working on my devices.

The only feature I really appreciate and use in Koreader is nightmode (invert colors, along with the excellent fit-to-width and scroll mode). Otherwise, particularly with multi-column pdf files, the inbuilt reading app in Pocketbooks is better than Koreader.