"Now looks like a winner"4.5 starson by mzungu45
Pros: Very clear text, reads PDF better than first DX, works as a basic web browser with no charges using 3G (not realistic with earlier DX); long battery life
Cons: No color, understandably slow and very basic as web browser
Summary: With the right kind of cover (available from third party), the Kindle DX can be propped up. It's hard to find a book as easy to read as the Kindle DX in that position. (Even with a reading stand, one needs to deal with the pages which often won't stay in position.) The ease of reading is, of course, mainly due to the clarify to of the font (which can be adjusted), which is one of the Kindle DX's strongest features.
For the first time a Kindle reader is genuinely usable for PDF files. This is partly due to the new hardware and partly due to software improvements which, for example, allow zooming. This does require some adjustments on the part of the reader and may not offer the perfect PDF reading experience, but it works acceptably (without color).
Another first is the existence of an adequate even if basic web browser. On previous Kindles this was either so slow or so primitive that it was, in my experience, too frustrating to use. But on the new Kindle DX, one could reasonably go online to read email, check the weather (radar maps are, of course, sluggish), or read an online newspaper, and this can be done with 3G for free (unlike the iPad). Of course it won't work if you need color or fast graphics, so it's no substitute for a laptop and won't do what a 3G iPad will do. But I would certainly use it rather than pay the outrageous daily fees some hotels charge for wifi.
Overall, I think it is an excellent product worth considering if it meets your needs, understanding its limitations.