I believe you already bought the DX, but let me give you my opinion.
I mainly read computer or IT related books. For those, I need a big screen, so programming code won't cut off (6 inches screens are too small) These types of books are usually thick and heavy, over of 1k pages ? So I though a DX would be a good idea. Well ... I used it for a few months and while not too bad, it was a painful experience.
DXG shines or should shine with PDF documents but there are limitations :
-Lack of proper PDF support or features, like annotations
-Page turn is too slow, more than the regular Kindle
-Amazon has not provided firmware upgrades in more than a year, that's a bad sign for a device that in terms of technology, is an "old man" now.
-When reading technical books, jumping from one chapter or page to another one is a pain.
-Too expensive for what it really is, a eink device
For all those reasons, I sold it and buy an iPad instead. While not eink, allows annotations and bunch of others PDF features via GoodReader app. iPad also gives me color and it is close in price to Kindle DXG but with a big difference: I can do more than reading and way faster.
Now, with so many new eink devices and touch screens, I see the Kindle DXG as a Dinasour. So unless you really want a eink screen on that size and you don't mind spending the 300 plus on it, my advice is wait and/or buy a tablet instead.