IMO, if you just want to read, a Kindle, esp. a Kindle "white" or whatever they call it, is the best. It is lightweight, thin, & lasts a long time on a charge.
If you want to browse the web and/or do email, then getting a full-fledged tablet is probably better. Tablets are usually heavier and don't last as long on a charge, but do have color! I have an iPad and use the Kindle app on that...it is heavy compared to a Kindle, but I mainly leave it in the house and/or read in bed.
FYI, for $0.99 you can get the complete collection of Robert E. Howard's Conan series on your Kindle device...I think I'm reading through this now for the 3rd time, when I get to the end, I just start over again. I don't know why, but it is extremely satisfying to read about all the bad guys dying, usually by Conan's sword cleaving through their skulls all the way down to their breast bones, with their brains spilling out...
https://www.amazon.com/gp/product/B01921JHGK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1