Here's an assessment from The Washington Post's Rob Pegoraro:
"Amazon's Kindle dominates this category but continues to suffer from self-imposed compatibility problems - the usage controls Amazon embeds in its e-books prevent you from using them in hardware or software not approved by the Seattle retailer and also forbid such customary practices as lending your copy to a friend. Its e-ink screen, meanwhile, exhibits the slow performance and low resolution of an early effort. A crop of new e-book readers - for example, Barnes & Noble's Nook, Plastic Logic's Que and Sony's Reader Daily Edition - promise better features but won't ship until the end of this year or even later. If you simply cannot live without an e-reader, get Amazon's basic Kindle model, not its bigger Kindle DX - but realize that a few months from now you may regret jumping into this market too soon."