All the people mentioning Kobo favorably in these comments... is the main selling point that the DRM is easily breakable, or is it a superior reader or marketplace in other ways?
As a counterpoint, I bought a kobo (clara?) two years ago, and ended up hating it. It was a lot of minor things that added up. Spuriously turning on in my pocket/bag constantly and ruining progress (the power-on button was poorly placed and very sensitive). Forcing a single font for every book. Page turns were often noticeably slow. Libby/Overdrive integration often spuriously re-downloaded books and lost my progress.
It was never clear to me whether I got unlucky with a bad device or not. But none of my issues screamed 'broken' rather than just 'annoying' so I assumed it was normal.
I dislike the kindle ecosystem as much as the next person, but I've found the hardware so much better and more reliable that I ended up going back to kindle.
The positive vibes in these comments are leading me to reevaluate and think that maybe something was indeed wrong with my device.
You can sideload books on Kobo over USB they parse the expected formats epub/pdf/html without problems.
There is custom firmware available and a homebrew app community.
I find their default interface is also good and can read anything without mayor problems, books, web & comics.
My reader Elipsa 2e is also great for taking notes and supports notes in book pages, though that specific model isn't supported by the custom firmware.
I switched to kobo for a while but I thought the hardware itself was inferior. Maybe they fixed it but I couldn’t dim the screen low enough to not annoy my wife while she tried to sleep. It felt cheaper too. I begrudgingly switched back to my old kindle.