Originally Posted by Gizmodo
I have to say, it is this Windows-only, iTunes-wannabe PC reliance that hurts the Sony Reader more than anything, especially because Sony Electronics will never admit to being as bad at software design as they are good at hardware design. The extra $100 for the Kindle means freedom from the PC—if at the same time it means a shackle to Amazon and its potentially limited file friendliness. When you talk to regular non-geeks, downloading books—and those all-important magazines and newspapers—directly to the device makes the most sense.
A very nice summary of the differences!