I've created a comparison, on scale, between the Kindle Paperwhite and the Aura One. 1 mm = 2 pixels. The Aura One doesn't look that much bigger, to be honest.
Kindle PW: 169mm x 117mm
Aura One: 195.1mm x 138.5mm
It's less than three centimeter longer, and and just 2 cm wider than a 6 inch Kindle, but it offers a vastly bigger screen in that space. I'm at work (in the middle of my break); later I'll calculate the screen area to total area ratio for both.