> PDF documents on the other hands... they render just right, everywhere. I have to zoom and scroll,

To me it feels the other way around, if I have to zoom and scroll, they render just almost right.

And that almost is extremely important for actual reading. If you're quickly skimming a PDF, sure. But to sit down and read for 30 minutes? One hour? Fuck zooming and scrolling. My kindle just displays a page, and I tap it and it goes to the next page. Can't really get a much better reading experience than that.