Honestly, I’ve been tempted by a Kobo lately; I have a lot of Star Trek RPG and comic book PDFs/ePUBs that I got through Humble Bundle over the past couple years.
Kobo seems like the least horrible brand I can get for a reasonable price with a reasonable screen quality; as pleasantly simple and reliable as they seem, and as nice as electronics re-use is, I’m not sure that one Sony e-reader that’s as old as my younger sibling fulfills my use case.
Though honestly, if you have other recommendations for a Linux-friendly color e-reader, I’d be glad to hear them.