Though Boox makes my own favorite e-book device ... but you can also pay another $170 for a case with a built-in keyboard. I got one of them to test out alongside the Note Max, and I would ...

That's why the Onyx Boox Note Air4 C, a $500 digital notebook and annotation tool, offered an alluring alternative: Mark up e-books and PDFs as much as you want -- and in color. I was intrigued.