My initial thoughts about the Kindle DX:
The price seems surprisingly reasonable. The iRex with an A4 size screen was over $800.
I’m not convinced that textbooks are workable on an e-book reader. You don’t read textbooks linearly. (Or at least, I never did.) The ability to flip around between marked locations is limited on the Kindle 2, and I’m guessing it will be on the DX as well.
On the other hand, the size and weight benefits are hard to deny. However, I never used to carry multiple textbooks around with me. Maybe American students’ habits are different?
It wouldn’t work for me as a general purpose device for reading novels as well as PDFs, because it won’t fit into a shoulder bag or reasonable size backpack. With a screen that big, it’ll be scarily easy to break by banging your bag against the corner of a table, unless you get some kind of metal hardcase.
Newspapers? Maybe it’s just me, but I don’t see the ability to display text in multiple columns as that big of a win. Consider that most people under the age of about 50 get their written news from the web, where a single column for the stories is the rule. We went through all the madness of trying to make electronic pages look like newspaper pages ten years ago; it didn’t work as well as a simple clickable table of contents. I bet the newspaper guys think going back to multiple columns is a great idea, though. As for diagrams, the existing Kindle can display those fairly adequately, it’s mainly being held back by the content producers failing to include them.
What about magazines, which generally require color? If I’m going to be spending a big chunk of cash on something with an A4 screen, I want to be able to read Scientific American on it without compromises.
Overall, I’m more skeptical about this than I was about the original Kindle. I think I’d advise waiting to see what Pixel Qi come up with, not to mention the CrunchPad.