How To Choose CD/DVD Archival Media Ã‚Â» Ad Terras Per Aspera:
For comparison, DVD-R includes one profile, optimum power output based for that one profile only and uncalibrated towards what wavelength it is for, less precise laser power settings, and no other additional information. Typically, DVD-R burners have to already know how to burn a certain piece of media (and include this information in their firmwares) before they can properly burn to it. New media often is not properly supported.
In addition to the optimum power control profiles, DVD+R also gives four times more scratch space for the drive to calibrate the laser on; more space can only improve the calibration quality. So, in short, DVD+R media exists to simply produce better burns and protect your data better.