In 1980s there was a tussle between VHS and Betamax technologies. VHS (Victor Home System) and Sony's Betmax were two different standards in Video tapes. People were confused as to which video tape to choose. Twenty five years later now there is a similar comparison in DVD technologies. They are DVD+R and DVD-R.
The use of DVD writers is increasing tremendously. Though the DVD disks are same, the DVD burning methods differ. Among these two technologies DVD+R is a more advanced technology. That is why these DVD+R disks are expensive compared to DVD-R. DVD-R is a comparitively older technology.
Now the next issue is your DVD burning software. Some buy DVD burning software without checking whether that DVD burning software supports both DVD+R and DVD-R disks. So though it is a bit more expensive get a software that supports both DVD+R and DVD-R technologies.