Best overall e-reader value
Amazon Kindle Paperwhite (2015)
The Kindle Paperwhite gets an HD screen, and while it isn't as big an upgrade as you'd think, it's a welcome addition, incrementally enhancing the Kindle reading experience.
Best ad-free e-ink reader
Barnes & Noble Nook GlowLight
While it doesn't necessarily beat the Kindle Paperwhite, the $119 Nook GlowLight is an excellent e-reader that's strongly worth considering if you don't want to buy into the Amazon ecosystem.