Thanks so much, I had guessed this was the case(especially after not seeing this information in any guide or on the forums here after searching through several pages) and then had seen one guide saying older DVD+RW drives could only burn to DVD+R discs and got very confused. I wanted to make sure.
There are a number of DVD+RW drives that cannot record DVD-R/-RW discs, but all drives capable of speeds equal to or greater than 8X are dual drives that can record both +R and -R.
The first DVD drives were DVD-R, followed by DVD-RAM (which could also record DVD-R.) When DVD-RW was introduced, HP, Sony, and Philips decided to introduce DVD+RW, using "+" as a clever marketing slap at the DVD Forum's "dash R" version, causing people to refer to the DVD-R as a "minus R." The first HP and Ricoh drives recorded only DVD+RW. Within a year DVD+R/+RW drives appeared. There were a few 4X +R/+RW and 4X -R/-RW drives, and then a dual format 4X drive appeared from Sony. Once drives went to 8X, all were dual format versions. Your drives are relatively new models and most probably capable of recording both formats.
There are two reasons I can think of to choose one over the other if you have a dual format drive that can do both:
1) one or the other has better playback compatibility on the DVD players you own. Some early players intentionally refused to play DVD+ discs because they were not official DVD Forum media. Some DVD players simply work better with the ADIP information on DVD+ media than with the pre-pit system used by DVD- media. Experimentation with your DVD players or the players of anyone with whom you exchange discs will guide you. DVD+ media do have an advantage in that they can be disguised to appear as regular DVDs if the book type bit setting is altered before recording. That gets around the problem of recordable discs not playing in the oldest DVD players or of DVD+R discs not playing in early Panasonic recorders and players.
2) One or the other has better recording results in the drive you are using. This is not uncommon. You can record a sample of each type in your drive and check the recording quality with a utility such as K-Probe for Lite-on drives, Plextools for Plextor drives, or Nero CD/DVD Speed for most other drives to get an idea.
If there is no significant difference in quality or in compatibility, then it makes no difference which type you choose.
To be on a little safe side try using DVDR- first if you run into a player that won't play them use DVDR+ and book type them to DVDR- and they should be fine . I just use DVDR- and they play in all my stand alone players, so I only use Verbatim DVDR-
