The PDF support is pretty good now. I would mainly use it to read free newspapers so I tried today's AM New York issue. You can scroll through the pages in portrait mode with fitted width, read the headlines and then zoom to 100% when you find an interesting article that you want to read. This works pretty well with a reasonable speed.
The downside is: it still crashes sometimes while scrolling through the pages, and you'll get kicked back to the library
So that's kind of a bummer. Have to say that AM New York is the only PDF I've tried so far so I can't judge on other PDF documents. I wonder how much the battery life has improved though.