I've tried both live and firmware version.
I moved back to stock firmware because the pdf reader is far from usable (the fonts are too small, but there are problem on zooming). The stock pdf reader is readable (although it's sort of small) at the largest zoom level. (problem exist even for firmware version of OI)
But since then, I've decided to convert pdf to rtf by Acrobat Pro. I'll give the firmware version another try.
Of course, if there is a fbreader (even old version) on current firmware, I'd like to know.