Kindle-lightweight, great for reading, backlit for reading in the dark or bright sunshine and battery charge lasts for ages as long as you have wifi switched off.
The two extra advantages of my new one, (I used to have a keyboard Kindle) are
1. It also allows me listen to kindle/audible books via bluetooth.
2. It has dark mode -white text on dark background. Less disturbing for DH when I’m reading in bed at night.
iPad/ipad mini? Good for all the things Kindle doesn't do.
Great for contacts, information, games and puzzles, reading ebooks, listening to audio books etc.
Weighs more, needs a bigger handbag, battery runs out faster, not good for reading in the sun.
Having both is a good option-and then, of course, there’s your phone.