Other than my work monitor, my e-reader gets the most amount of use on a weekly basis. I aim to go through 100 books a year, and these days, I use Kobo's Libra Colour because of the E Ink Kaleido panel, physical controls, and USB-C connectivity.
While I like the Libra Colour a lot, the 7-inch panel means it goes in my EDC bag — that in itself precludes me from using it when I'm out and about. This is where the DuRoBo Krono comes in; this is an e-reader as well, but it has a design that's similar to most modern phones, and the 6.13-inch screen means I can just slip it into my pocket without any issues whatsoever.
