Well, reading a number of reviews and guides, it seems previous e-book readers didn't seem to handle PDFs well and most times didn't handle maths well either. That's why most guides etc. recommend tools like K2pdfopt to convert PDFs. But this year I though I'd give it a shot and test to see if the myths were true and I'm happy to report that it is not true for the new models, PDFs work great and maths are flawless.... at least for the Amazon Paperwhite 2015 model.
Here's excerpts from my thesis (available open access here) displayed on the device. ;)
You can zoom like on any other tablet, with much slower update rates, but not a major drama since once you get the view you want, you can read it like paper.
Portrait Mode Zoomed
I usually use the landscape mode, where each page is shown in three sections.
Surprisingly, the default PDF behavior was better than the converted PDF files were. Battery life is about a month and the reader also has back illumination for night reading, though would preferred a night mode (white text and black background) like some apps on Android tablets, but no biggy. I did find using the free Calibre to rename and reorder PDFs a must as the reader doesn't read the PDF meta data, so the PDFs are shown with filenames of the PDFs on the home screen. Adding sub-directories would be nice too on the home screen.
All in all, I would highly recommend the reader to scientists for reading scholarly articles and properly displaying mathematics.
Cheers Shakes - L3mming