PDF support is OK, but I loathe the use of PDF in general for ebooks unless it is used to display graphics-heavy or layout sensitive content. It has no place in ebooks where displays and navigation vary so much between devices.
In OI, there are a number of settings that you can adjust that make viewing PDFs easier. By default the "pan" increment is 50% which for a lot of content means it jumps off one side of the page to the other - try setting the increment to something smaller.
Plucker is a format that is becoming less common unfortunately. The Gutenberg Project used to publish books in it, maybe they still do. It's main advantage for me is that it is an excellent format for converting web pages for offline use, as navigation and links are all preserved. Navigation isn't very useful on the Hanlin V3 hardware (great on my touchscreen devices, though), but I still use it for long articles or where content is published as a single page.
As a format, though, Plucker is a dead end - in that there aren't any good tools for converting from Plucker to anything else. This is a factor that I think should be considered when choosing any format for a library.
However Plucker is still the format that best integrates into my web browsing and online and offline use:
http://hindesite.wordpress.com/artic...book-workflow/
Now that my Hanlin supports Plucker I'm a very happy camper.