An article on the Christian Science Monitor points out that Kindle may be at the top of the food chain now, but that position makes it vulnerable to those who seek to cash in on the growing eReader market.
Nature has nothing on the technology market when it comes to ruthless competition. And since Amazon is pretty much a T-Rex when it comes to stomping other retailers, the evolution of eReaders should be an interesting contest. It's a growing market, and there's room in it for an assortment of eReaders, if each of them can find their niche audience—students who need textbooks, periodical subscribers, casual readers, geeks who want multipurpose, etc. Those who can't may become fossils before their e-ink is even dry.