Amazon launched the Kindle DX in May 2009 as their bid to enter the academic market. The KDX was the first Kindle model to directly support PDFs, and Amazon hoped that the KDX's larger 9.7" screen would work as an adequate replacement for paper textbooks. Amazon even convinced a number of major US universities to launch digital textbook pilot programs based on the Kindle DX.
This was of course before the launch of the iPad. That was during the middle years of the ereader bubble, a time when it wasn't a crazy idea to believe that an E-ink ereader with poor PDF support and no touchscreen could be useful for textbooks. But now we know, largely thanks to those pilots, that the Kindle DX is too slow and too feature limited to work well with textbooks. It's not nearly as fast as your average textbook app on Android or iOS, and it also has fewer features.
And if the lackluster performance wasn't enough to kill most school's interest in the Kindle DX, the lawsuits filed by visually impaired students did. In 2009 several students filed suit in partnership with the NFB to block the Kindle pilots because the students were blind and thus couldn't use the Kindle DX. Those suits weren't settled until mid-2010, but naturally that put the kibosh on large-scale adoption by schools and libraries.
This ereader was updated in 2010 with a faster screen and more features (and Amazon even rolled out a firmware update in early 2011) but this ereader has largely been neglected since then. It might be new on the shelf today but it is still a circa 2010 ereader. I feel a similarly priced tablet would be a better buy.
This week's revival of the Kindle DX isn't the first ereader that Amazon has brought back, and like the Kindle Touch this offering might only be temporary. So if you want one you should act fast.
On the other hand something tells me that this ereader might be available for longer than the month or so that the revived Kindle Touch. Amazon has not only brought back the KDX, they also updated their menus to promote it again. The Kindle Touch, which was briefly available for about a month earlier this year, was sold but not promoted.