I stand corrected on the Cybook and will amend my statement to say "the most popular eInk readers." I doubt Cybook has much market share, especially in the USA.

I agree that the software keypad on touch screen readers doesn't work well due to slow reaction time and eInk refreshing time. A keypad like the Kindles is a bit better, though a keypad with a softer touch would be even better. The Kindle keypad requires thumbnail pressing (in my case) and a hard press at that. That makes using it almost as clunky as the Sony software keypad. Perhaps a keypad with the response and feel of the one on my Blackberry Curve would work better as I can type a lot more quickly with it than that cumbersome Kindle keypad. But in reality, I doubt that a good key entry system can be designed for eInk readers due to the slow refresh rate.