E-Readers coverage from Mon Book Pro.
On the makers' own documentation, reMarkable is the focused note tablet, Boox is the do-everything Android slate, and PocketBook Era Color splits the difference on a budget.
IPX8 means a device survived submersion under lab conditions — it is not a lifetime guarantee, and chlorine, salt water, and hot showers each change the math.
You can put your own DRM-free EPUB files on every mainstream e-reader — the safe method is Send-to-Device services and USB copies, never third-party stores of unknown origin.
Carta 1300 gives you the sharpest black-and-white page; Kaleido 3 trades some sharpness for color — here is how the two panel families actually differ.