I just noticed yesturday that Plextor has released firmware 1.04 for the PX-708 drives.

From Plextor's site:

*Support added for newer 8x DVD+R media
*8x write support added for additional brands of 4x DVD+R media
*Support added for additional brands of DVD+R and DVD+RW media
*Support added for additional brands of DVD-R and DVD-RW media
*Improved write performance for DVD+R and DVD+RW media
*Improved write performance for DVD-R and DVD-RW media
*Improved write performance for various brands of CD-R media
*Corrected possible conflict between different application softwares when recording DVD-RW media
*Corrected possible "No Seek Error"during write of DVD+R medium while using Nero

Update Here : http://www.plextor.com/english/support/downloads/firm_708A.htm