Thanks for calling my attention to the differences between the DMR-ES20 and the DMR-ES30V.
The DMR-ES20 Operating Instructions mention that DVD+R media may be played on the ES20 if it has been recorded and finalized on another machine. DVD+R media is not approved for recording on a DMR-ES20. DVD+RW media is not mentioned, perhaps because it had not yet found its way into the marketplace when the design work on the ES20 was completed.
The DMR-ES30V Operating Instructions mention that DVD+R media may be recorded and played on the ES30 but DVD+RW media is not mentioned as approved for recording on a DMR-ES30V.
Beginning with the 2006 models all formats are "supported." As many Panasonic users have found, Panasonics are "friendlier" toward DVD-R formats than DVD+R formats. It's best to stick with a "friendlier" format than taking chances with "less friendly" formats, especially now with the proliferation of inferior 16X media in the marketplace.
Owners of older machines should make sure that they run the latest firmware updates to "work with" whatever good quality 16X media may still be in circulation.
It appears that high quality 8X media is starting to disappear from the marketplace. The time is now to buy whatever quality 8X media may be found before it's gone.
While some recent computer DVD burners claim speeds up to 22X, I've yet to even hear of any HDD/DVD recorder capable of high speed dubs that exceed 8X. Wajo suggests that the Magnavox 2160 may have a DVD Drive rated/operating at 8X. Yes, my 2160 high speed dubs are "blazing fast" well, sort of, because the 2160 is much faster than my Philips 3575 or Magnavox 2080, but 8X? Well . . .