Here is one other interesting observation I made about the 1.06 firmware for the PX-708A.
With 1.04, there would always be one 'unreadable' block at the end of any burned data CD according to Nero CDSpeed 2.11. This never affected the readability of the disc, and there were never any problems copying any files from it. (And yes, I did test with numerous CD drives. And it never happened with burned DVDs.)
But with 1.06, there is no longer an unreadable block at the end of the disc. Yay!
I don't know if this means anything important, but I just thought I'd mention it.