I have a Supernote A5x, use it as a note pad, annotate cad plans on site and sketch basic renders on it, I use it a lot at work.

loaded it up with the kindle app, but I find it's a bit annoying to use the app, so I upload books as a pdf to a folder on it and that works. It's just a shame I have so many books locked into the kindle app. But it might get better with an update one day.