most e-ink readers currently implement the same generation of e-ink technology (Vizplex), however, each manufacturer obviously implements the same technology a little differently, having seen/used/owned quite multiple e-readers, I can honestly say the nook has the best screen contrast that I have seen, closely followed by Astak Mentor Lite and Sony PRS 300. And based on what I see in target, the Kindle's screen crontrast is not as good as the nook - I don't have idea how anyone would rate Kindle's display better than the nook's. Nevertheless, the current generation of e-ink is still a little too gray on the background. To say it's paper like is more of a marketing hype than the truth, when they say "paper-like", they must have meant very old newspaper on recycled material; The cheapest paperback books still outperform the best current generation e-ink reader. Here is a side by side comparison of the screen for a real book, sony, the nook and the Kindle DX.
