TITLE: Kindle as a Tool for Mathematicians?
QUESTION [29 upvotes]: UPDATED: 1/15/2014
I originally wrote this post in 2010, when I was looking for alternative ways to store and transport papers. I had my laptop, but due to its weight, limited battery life, and the LCD screen, an e-reader such as Kindle seemed like a good idea at the time. (Also, at the time of the original post, I had never owned a smartphone, let alone a tablet.)
Aside from the Kindle, are there any other electronic tablet or pads, or other devices that you'd recommend for this type of purpose? What are some of your experiences?
As for my self, I purchased a Pocketbook Reader 602 from PocketBook International four years ago. At the time, it seemed like a smart purchase, as it PBR handles a while array of file formats without needing to convert anything. However, I don't use the device as nearly as much as I thought I would. 
The device itself works the way it should. It is a bit slow with the page rotation. And as user641 points out, the PBR can be a bit sluggish with larger files. The text-to-speech feature is completely useless when it comes to reading math. I tried utilizing the internet connectivity. While it is amusing to see websites in e-ink, in the end it's too sluggish to be of any use.
Here are a few things that I had originally thought would be convenient, but wound up being an annoyance instead.

Lack of Touch Screen Capability. I purposely chose the model that didn't have a touch screen capability. Reports of glare and the idea of getting smudge on the screen led me to that. However, the alternative is an extremely painful, unintuitive, tedious navigation.
Small Size. I opted for the small size of PBR 602 for its portability. While I have no problem reading novels, for math this is just unbearable. The slow page turn / search interface / zoom makes the problem even worse. Basically, reading anything that requires jumping from one part to another, looking up index or keywords, is extremely painful. 

Note that the small size wouldn't be as big of an issue, if the interface was quick and seamless. For instance, I don't find reading math on my smartphone as painful.
I still use my PBR 602 from time to time. In fact, I go through periods where I would use it extensively. Unfortunately, its inconveniences prevents it from regular usage.

REPLY [3 votes]: I will share my experience here.
At first I also bought a Pocketbook e-reader, specifically the 902, which has a larger screen.  It handled both DJVU and PDF files, which was important to me.  The DJVU rendering was slow, however, and it had serious lag issues with large files.  But all the math was perfectly rendered, zoom worked, etc.
I eventually got rid of my Pocketbook because I found the device somewhat unreliable.  It was also clear that reading DJVU files on an e-reader is not the joy you might think it is.  Specifically, these are normal (A4) sized pages, being shrunk to fit the screen. I downloaded a few programs to help with the margins, but still, it was difficult/not worth it to read DJVU files this way.
I then purchased a Kindle DX, which can handle PDF files, but not DJVUs.  The Kindle is an incredible product, and works very well.  Still, it will lag on larger PDF files, and several times I have had to trim margins on my laptop before putting them on the Kindle.  This is really nothing to do with math however: I don't think there are any e-readers out there which handle PDF files like this well.
Now there a couple of options.  One is to convert the PDF files to an AZW (or even MOBI) file.  In my experience, this fails miserably.  Even without any formulas/math type, the spacing and sentence structure is essentially ruined.  With math? disastrous results.  And if there are pictures, forget it.
The other option, which isn't always available, is to get your hands on the TeX source.  I use this option for any arXiv papers I download, for example.  There you can resize the font, margins, etc., to optimize for Kindle viewing.  There are measurements out there which give exact dimensions for the viewing window of a Kindle. This option (which again, isn't always a possibility) is certainly the best.  Reading a paper on the Kindle this way is just as enjoyable as reading a hard copy.
In the end, the books I do have as PDF files I trim myself (using pdfTK and a Java program called Briss), and then put them on the Kindle as PDF files.  I view it rotated 90degrees, because this increases the magnification.
The articles I can get as TeX files, I adjust the margins/font size etc. (this is based on the paper itself; for example, large figures require different processing than a short, all-text paper). Then I convert to PDF and put on my Kindle.  Again, these are the nicest PDFs on my Kindle.
Finally, I would like to mention that several prominent math books (a few by John Stillwell for example) are now available in Kindle format on Amazon.  I haven't purchased any of these, but presumably the publisher simply changed the margins/text size in the TeX file, as I do for the articles.