I was pleased to learn the Sony Reader is just as big, if not bigger than your average paperback, which means your eyes won't have to strain to look at the screen. I was also pleased to see how thin the reader is, and while I love the feeling of a nice paperback by the pool, I think I'd invest in a Reader to use when I am traveling.
The device uses a rechargeable lithium-ion battery (it apparently lasts for up to 7,500 "page turns"), and it recharges in about 4 hours when using AC wall charger or 6 hours with USB charging from powered computer. (Anyone besides me think that is a long charge time?) It costs $350.