Now that I’ve had this up and running for a few days, thoughts are: definitely worth doing if you like tinkering and customisation.
It’s really easy to do so; can be done entirely on the Kindle. The Installation Guide walks you right through up to installing KOReader. I also added the Storefront plugin as well, which makes adding other plugins as easy as downloading apps on a tablet.
It took a little bit of fiddling around with KOReader to get it to a style I liked, and I think the UI can be a touch over-complicated — but easily mitigated by the plethora of UI extensions available on Storefront. I’ve gone for Zen UI at the mo’.
I’m loving Storefront as well; I’ve downloaded a StoryGraph plugin for tracking, a couple of direct sideloading plugins so I can browse & download directly on the Kindle, a Libby plugin so I can still borrow from the local library, removed the ads from my lockscreen, customised the lockscreen, and added some little widgets to just make the Kindle itself more aligned with my aesthetic preferences.
My Kindle isn’t connected to an Amazon account, but it apparently still works with all the usual functionality.