An interesting review and well worth reading right through to the end, as there is also an update at the end after further usage and software updates. It is always going to be a question though of balancing what you specifically what to do vs what you are prepared to pay.
A Kindle is a dedicated device which has excellent battery life and is good on the eyes. An iPad / Android tablet is a lot heavier, has lots of distractions, with worse battery life and can be harder on the eyes with its backlight. This Onyx Boox Nova Air is something between the two with better battery life, better on the eyes, and has note-taking ability with a stylus.
It is a bit pricey, and of course the e-ink screen is going to be slow on the refresh, but if note-taking and reading are to be the primary use cases, it may be well worth considering. As it runs Android, the Kindle app can also be installed, and it gains access to the massive Kindle online store too.
See Onyx Boox Nova Air review: Kindle who?
This Android-powered e-ink tablet has a lot to offer