I traded in my K2 to get a DX because I wanted to be able to put my Role Playing books on it, and most Role Playing books are currently available in pdf. I like it, and have had good luck with most books that I have loaded on it. Occasionally, I have had a few newer release pdfs fail to display all of their graphics, but all in all I have found it to be quite useful.
Also, since I got it right before GenCon in early August, there have only been a few places that I have not carried it along with me. I got an M-Edge leather cover for it and carry it in a smaller, netbook sized messenger bag that is padded for carrying a computer. So far I have had no problems with durability. I take care with it and pay attention to what I am doing while handling it, but so far no issues!