I'm new here but saw this site several times. Now am going to visit more frequently as I'm evaluating the DX for replacement of a multi-thousand-page thick library of scientific papers!
Yep, I've got the DX primarily to streamline my collection of real scientific papers, which are in PDF. Most of them are two-column ones, such as
http://memetracker.org/quotes-kdd09.pdf
Now it's hard to read it vertically, but it's OK in landscape. I wish I could automatically split each two-column page into 2 single pages.
Some other impressions: I got the Amazon leather cover for it and it's extremely handy when reading while walking, and in general. It's hard to grasp the Kindle while walking without hitting some keys.
Another tip is, get the replacement USB cable for office, so you have one at each location where you'd be tempted to transfer files from the computer.
The best thing which could happen to science is when the Papers application,
http://mekentosj.com/papers/
will work with the DX to leverage their amazing management of individual PDFs. It already syncs to the iPhone, wirelessly and beautifully, and they are waiting for Amazon to reply to their proposal to develop for Kindle. I suggest all of us with interest in PDF management for mobile reading voice our desire for it, along with the folders, to AMZN!
Cheers,
Alexy