No its not a difference. IE thats a difference in your eyeballs and my Tablet screen is almost the same size as the Sony screen. 7 inch screen on the tablet 6 inch screen on the sony. and as I said its almost readable at 640x480 on my 4" screen Zen Vision. so no its not screen size for the most part its just colors. its a pitty cause it would be awesome to read digimags on the sony reader so convenient.
What screen size DOES effect is your ability to read if you do not have the greatest vision. IE if you can not see "finer" detail. for example 1920x1440 is perfectly readable to me on my 21" monitor for my dad it might as well be a blur.
but that is a VISUAL limitation in my dad's eyesight NOT a limitation in the screen itself.
with the reader it has enough pixels and it has enough inches. It just does not have enough shades of color.
Chris Taylor
http://www.nerys.com/