+1 for kobo, the e-ink screens are great, and side-loading epubs and other formats is super easy in any OS (computer sees them as a disk), also installing custom firmware on them is possible (if you're into that), i've always really liked mine

one thing to keep in mind is that none of the e-ink readers are great with PDFs (don't know if that changed with the latest ones but i'd be surprised) due to lack of text reflow, so if you mostly want to read PDFs you're better off with a tablet