Plastic who? Plastic Logic's going to need the backing of Barnes & Noble's e-bookstore to get past the "I need to explain who I am before I can explain what I can do" problem. Amazon and Sony, on the other hand, are household names.
You could argue that Sony is better known all over the world than Amazon. But it's been the Kindle that's thrust e-readers into the popular limelight and inspired a million think pieces everywhere from scholarly journals to breathless IT blogs about the death of the paper book and whether that's really something an e-reader can accomplish. The point? When most people think "e-reader," the first thing they think is "Kindle" (pictured). That's a big plus for Amazon, which has gone to great lengths -- from iPhone exposure to buying up app competition such as Lexcycle's Stanza -- to make sure its name stays synonymous with the market.