Bookshop.org★★★★☆A good place to shop online for books and still support indie bookstores. They’ve started selling eBooks too, in standard ePub form. The reader app is a bit rough around the edges, but works well enough on a regular phone or tablet…just not on an e-ink touchscreen (yet?)
eBooks.com★★★★☆An eBook seller with some actual business ethics. No hardware (which simplifies things), but they have an app for Android and iOS, and any DRM-free titles can be downloaded and read on just about anything.
Kobo (eBook store and readers)★★★★☆A solid alternative to Kindle, from the eBook selection through apps and hardware. The app works well on my eink tablet without too much tweaking, though it still wants to sell me more books before I can open the one I want to read.
Onyx BOOX Poke3★★★★☆I’ve been using the Poke3 as my main ebook reader for a couple of years now, mainly because it’s a convenient size, has a clear e-ink display, and can run the Android app for any eBook store.