Why don't you browse around the forums which give info & advise about the various forms of readers:
https://www.mobileread.com/forums/forumdisplay.php?f=123
If you're within reasonable driving distance of stores where you can actually try out various readers, that would be great. Also, make sure & check with the return policy of the store you plan to buy from (Brick & Mortar, or internet). Some are very liberal, others, once you buy, it's yours...no returns unless defective.
I had gotten a devise at BJ's & had 3 weeks to try it out & still be able to return for a full refund. The Sony store, at the local mall would NOT let me return a purchase unless defective. Also, neither would Borders. Ask lots of questions!