A friend sold me an original kindle for maybe $20 one time. I used it to read about 75% of Orson Scott Card's novels within the Ender's Game series. After about a year, it stopped turning on. It was probably 7 years old by then, so I just got rid of it.

I bought a 2" thick sci-fi book a few years ago, "Pandora's Star". It seemed pretty interesting, but way too much book to carry around. I got a kobo and put what I vaguely recall was named "koreader" on it. It was pretty nice. It stopped working after 6 months, though. I took it apart, and at least one power management IC is shorted out. Its e-ink display permanently says, "Sleeping..." It's been a paperweight on my nightstand for about 2 years, and a minor source of anxiety for me. I don't plan on buying another kobo device any time soon because I hate e-waste.

My wife got me a kindle paperwhite to replace it, and it didn't take much work to get the same book onto it. I think I'm maybe 25% of the way through the book, but I can't really say because I don't understand what the numbers in the lower corner mean. I also printed the Rust programming language manual to PDF and managed to copy it onto the kindle without much fuss.