These devices are not one size fits all so I don't expect everyone to agree but I do state which functions I value and why. It might be flowcharted so that others could navigate the minefield and make there own decisions when they come to a subjective choice.
Anyway, I started with this comparison grid
which is more up to date than the one I saw on this site which seemed to be pre-Kindle 2.
I was able to play with a co-workers 6" Kindle 2 device but I have this thing about keyboards...I detest them. I write software and use on 10 hours a day. I am using one now. I have tendonitis in the hands and fingers, carpal tunnel and tennis elbow in both arms all because of too much time on keyboards. That eliminates Kindle which in my opinion suffers from trying to be too much, doubling for a limited function Internet browser that is put to shame by any PC browser and has speed and color constraints. I'm content with the E-Readers being a digital book and PCs being PCs. 'Nuff Said.
Needless to say I was intrigued by the new touch devices and not excluding the Sony Daily Edition and B&N Nook from the candidate mix, despite their not being released yet.
The musts for me are mobile wireless and touch screen. Within a reasonable price range the larger the screen the better. That eliminates the so-called "pocket versions" as well as the Sony Touch Edition which lacks wireless. I want to be able to get the book I want when I want it no matter where I am. Wi-fi is not so important because I am never a short drive away from mobile access.
I am considering one for my mother-in-law who buys large print editions of books and I want to be able to lend her mine. She would need to amp up font size then rotate 90 degrees so lines would not be prohibitively short. She'd get fewer lines and would have to page more often...but she would be able to read it.
I considered the Irex DR800-SG but the touch will not work with your finger due to Wacom Pen Tablet technology. I have a stylus on my Windows mobile device and I always leave it somewhere. In general the thought and UI-friendly aspect of a well designed touch device design makes using it a pleasure and a breeze even for the non-technical.
I'd been shying away from the Nook with the 6" diagonal screen because the device size was larger due to that extra 3.5" color screen across the bottom until I saw an image showing how a soft keyboard occupies that space as opposed to crowding out the "page" as would otherwise have to happen.
Designwise that additional screen contains navigation controls which a much more adaptable than fixed physical buttons given that they can morph in an almost infinite number of intuitive ways depending on context...on what you happen to be needing to do at them time -- a better, more user friendly design in my opinion.
I like being able to listen to music at times which sweetens the pot though it isn't a deal killer since I can do that on my Windows mobile smartphone. But as long as it can play music I want SD card slot, giving me more memory that I will need until some day at which time these things play video too. But that day hasn't arrived...yet.
I read way too much not to make effective use of E-books so it is nice to also be able to make use of one of these devices. My favorite books are kept and referred back to often so the large capacity with annotation capabilities is very important.
I would like it to read to me like the Kindle in case I am driving. I have jacks in all my vehicles using male to male stereo earphone cables that allow me to listen when I drive. Sure, bluetooth would be even better but kills the battery. For me the advantage of this reading aloud function does not outweigh the Kindle's shortcomings. Besides, you can have everything, despite really wanting it. LOL.
The Sony Daily Edition shows promise and is slightly larger and has mobile wireless but costs $160.00 more and has a more limited library available than does the device from Amazon. They are less definite about release date than is B&N who vow that it will ship on 11/30/09. So I ordered a Nook today. I hate buying anything without a test drive but I don't want to wait until it hits the stores because there could be shortages.
I realize that not everyone values the same functions as I do so I find it silly to approach this as someone might approach some sort of religious war. At some point most devices will have all the best features. I predict that once these things cost $49.00 at Walmart every school kid in America will replace 30 lbs of books with a 10 oz. E-Book reader. Add lectures that are live wireless and streamable later with classroom collaboration via IM and shareable lecture and reading annotations to overlay class materials and school walls become less important. These classroom systems exist already, just a little before their time though. As technology improves, touchscreen PCs and E-Readers will converge and become less expensive and also be a great boon for oil-depleted, transportation-challenged societies of the future.
Given that my friends with Kindle 2's claim that they forget it's an electronic device and find themselves trying to turn the pages is enough to make those who claim the good old traditional book cannot be replaced seem less visionary and more luddite.
OK, maybe a little over the top ... or is it?