This photo of the Kindle on Amazon's site suggests that it is quite large indeed.
And they said it was not illuminated! <g>
OK, so it is 120% of the area, 225% of the thickness, and 113% of the weight the Sony (new Sony as that is the competition).
Would have expected it to be heavier. Must be either not very dense or all plastic (and indeed it looks to be plastic)...
Might be OK if the content and especially the price of the content is killer. We shall see.