Thre are DVD+-R/RW discs and DVD-RAM discs. There is very little difference between + and -, but some older DVD players can't play + discs. It really boils down to what is considered to be a "better" standard. DVD-R/RW is the good for almost anything, mainly DVD audio and video. To my knowledge, DVD+R/RW was created for storing files and stuff. It's sort of a DVD-R/RW V2. But even at that, both mediums are generally suitable for both. The only difference is how the laser is used to burn the data; when burning a DVD-R, the laser has a set "strenght", whereas in DVD+R the laser strenght is alternated every so often. DVD-RAM acts like a removable hard disc of sorts. DVD-RAM has faster access time that DVD-R/RW and can be overwritten god knows how many times. One does not need burning software to copy data to a DVD-RAM either.