A I had just started a reading jag on the DX, I didn't last long before purchasing a Kindle Paperwhite (Wifi). Nice device, touchscreen is fine (didn't really mind the buttons on my older Sony's or the DX though). Have used the Wifi and cloud to coordinate one book between the Kindle and the iPad (keeping the page numbers). I did like that functionality (didn't execute this in the DX 3g).
I've had serveral e-readers, and remain a fan of the technology: Sony PRS-500, Sony PRS_505 (the best looking e-reader, with the aluminum casing), Kindle PRS-900 (didn't like this one, shape or the fact that the 3g did not work in Canada), Kindle DX (like this device immensely, though a little expensive) and the Kindle Paperwhite.
What I've learned:
- Don't worry over-much about capacity - it might be fun to think of carrying 10,000 books in your pocket, but really, all that does is take time to find your "next read". Unless you have a reason to carry sets (such as all of Shakespeare), you are probably better served to carry 10 or 12 books max.
- Don't worry too much about the format of books - Calibre (http://calibre-ebook.com/) is a free software package that converts very easily and invisibly between formats. It also recognized all the devices I've tried to load books onto, and transfers books, and allows you to delete books from your device easily.
- I find that I don't use the Wifi or 3G very much - I find Calibre to be an excellent tool for archiving, storing, sorting and converting books to appropriate formats. 3G tends to add a lot of cost to the device - think carefully about where you will be loading books - if you have WiFi at home and work, many restaurants, think about how often you'd need the 3G capacity to load books. As you can load many books onto your device, you will rarely (if ever) find yourself "stuck". I find that I load from my PC library through a cable.
- Find a device that you like the feel and look of. Check out the screen - the "paperwhite" version(s) do look a little brighter than older styles. The embedded lighting seem to be relatively good on batteries and provide a seemless reading system. You can add booklights, similar to a "paper book", and this is a very small inconvenience, so I wouldn't consider the embedded light to be a must-have. Functionally, there are few differences between devices - screen size and shape, contrast, screen update speed (perhaps the most important of these differences, as a "too slow" update screen can get annoying), resolution (again, as you aren't typically looking at pictures, is not a hugh issue), capacity (see points above), 3G/Wifi/None, and presence/absence of a light.
- playing with the device(s) for a few minutes in the store provides you with enough information to figure out the playability of the device ("do I like the look?", "does it feel good in my hand?", "does it refresh quickly enough?").
- LCD, iPad etc. are not e-readers. They can do much more, can web surf, can display in colour, but are not the same devices as e-readers. E-readers have e-ink, which is a physical B/W set of pixels that spin to render the images (mostly text-pages). Once rendered, there is no additional power required to keep that image in place - it is physically "drawn" with the pixels. This is the main reason for e-readers - they can display B/W information clearly, have a high contrast/low glare display, and have phenomenal battery life (on the order of weeks or months, not on the order of hours).
- Not to downplay iPad and LCD readers, but they are simply another class of devices, and much more expensive now that e-readers are often under $100, and "max out" at under $200.
- e-readers may do other things, but those other things are not in any way a challenge to the LCD and iPad devices (e.g. you can look at pictures, or websites, but you can't really view video on e-readers). For web surfing etc. e-readers are not the appropriate choice - for reading books or documents, they definitely are.
Update: May 3 - have been reading on the Kindle Paperwhite and do like it. None of my prior e-readers (not counting the iPad) were touchscreen, so that's a nice addition (didn't mind the page turn buttons though, so not a giant addition). The "enlarge" gesture I learned for the iPad works on the Kindle to increase or decrease font size, which is easier than the two step process in the past.
The build-in light is nice as well, particularly as it has a "volume" control, so it is adjustable for different conditions - this is better than other lights I've used.
Didn't take me as long as I thought to get used to the smaller size again.