Features won't matter. Wired magazine had a great article about "Good Enough" tech.
http://www.wired.com/gadgets/miscell.../ff_goodenough
From MP3's to Flip Video to cloud computing and netbooks, what people want is accessibility. Accessible price, accessible content, accessible use. The first company that puts out a reader that meets those will flood the market.
It won't be wi-fi or resolution or page speed - it'll be accessibility (especially price) that drives the market.