It really depends on your personal requirements/desires. I have both the K2 and the DX and use both equally. Even though I have no requirement to view PDFs, my preference for reading goes to the DX for its excellent display size. More text and fewer page turns are a big plus in addition to viewing illustrations. Think of comparing the size of a paperback book to that of a hardcover. Which do you prefer?
That said, if your requirements include mobility and a smaller footprint, you cannot go wrong with the K2. I use it primarily for the extensive traveling I do but could just as easily take my DX as it is thin and lightweight (IMHO).
With Amazon, you can give the DX a try for 30 days and exchange it for a K2 if you find that would be a better fit for your needs. Win-win.
