I have been reading with my regular Kindle Fire for some years now, and I really like it for reading a regular book (such as a novel), which does not have any charts, graphs, or pictures of anything.
When I am reading something that I need to see illustrations, then I use the iPad instead, because it is much easier to enlarge the illustration and see what they are showing me with it.
Because I have my iPads,and iPhone, I never actually use the Kindle Fire as a tablet, even though it is functional for that, just like any other tablet.
I was browsing the Kindles on Amazon (someone mentioned they might be going on sale), and was looking at the dedicated e-readers, the Paperwhite and the Oasis.
The Oasis (for me) is way too expensive, (around $250) and not necessary; but the Paperwhite is fairly affordable and has good resolution for reading, plus has a light for reading in the dark.
I do not usually read in the dark, but it is nice to know that is possible. The battery lasts much longer than the Kindle Fire battery, and would only need charging once every 1-2 weeks instead of every day like the Fire tablet.
When I found one that was $129, and amazon lets you make payments, I was interested, and then I read that if you have Kindle Unlimited (which I do have), it was under half price (about $64 altogether), that was enough for me to decide I needed a new Kindle Paperwhite.
It should be here tomorrow, and I am looking forward to trying it out.
Naturally, I will still use the iPad for anything with illustrations, but for recreational reading, the Paperwhite should be perfect.
Here is a neat little comparison video that goes over some of the benefits and drawbacks of reading on the Kindle, iPad, and paper books.