The DVD-R format is the version that DVD Forum uses. They control the licensing of the actual DVD format and official logo. The DVD+R is used by members of the DVD+RW alliance.
It's two competing organizations that have a lot of the same members. It's like the difference between coffee or tea, they are both made pretty much the same way and do nearly the same thing but taste totally different.
I buy the DVD-Rs since I've never had a compatibility issue with them.
^^^^What he said. I use -r's also cause I've experienced problems with different dvd players not recognizing +r's. However I've also seen -r's not work in some players as well just not as many. I've got 2 sony dvd players, xbox, and xbox 360 and they all read -r's with no probs whatsoever.
Next time ask something difficult, like what are the differences between: DVD-R, DVD+R, DVD-RAM, HVD, EVD, HD-DVD, Blu-Ray, DIVX, DVD-D, DVD-ROM, DVD+R DL, DVD-R DL and DMD Oh yeah, can't forget the paper disc format.
The last batch of -R's I bought - physically stunk! (memorex). They have a strong burning plastic smell lol... (I have a +R burner and accidentally picked up the -R's for it). Fortunately my laptop will burn the -Rs, so I can use them.