I have an earlier 6" Kindle (Kindle 2 international version), and have tried to use that for reading technical papers that come in PDF form. I haven't found this a very pleasant experience. The typical formatting of PDF papers doesn't lend itself to reading on such a small screen. Usually I switch the Kindle to landscape mode, which often results in a readable font size. But then scrolling becomes a nuisance, especially for papers in multi-column layout.
Another problem is that (at least on my Kindle), you cannot annotate PDFs in the way you can annotate "native" e-books. This is relevant for technical papers, especially when you do reviewing.
It would be great if there were a program to convert arbitrary PDF (or just the PDF generated from the tools used for technical papers, i.e. TeX, Word, and ...?) to e-book formats so that the layout can be adapted to smaller screens and different font sizes. But such a program would be difficult to write, because it would have to reverse-engineer the intent of the layout. I don't know whether anything useful exists.
For PDF viewing, I'd try a touch-screen device with fast and easy scrolling and zooming. Maybe something like an iPad or a Kindle Fire.