The spiral tracks on CD and DVD are designed for linear writing, like tape. At least with tape you typically have two heads so you don’t have to perform two distinct operations. The enforced read-after-write of DVD-RAM negatively impacts performance, and is always going to be at least twice as slow as the rated speed, if not worse (consider retries). We would always recommend verifying data written to discs in an end-to-end fashion (the data read back matches the data in the original file), which is not quite the same thing as the drive checking the data it thinks you sent (or the backup or file system software generated).
Trying to make a CD/DVD drive work like a hard drive requires a degree of “witch-craft” that we wouldn’t involve in something we wanted to “backup”. You may trust the software writers, we are somewhat more skeptical. Authoring a disc with some thing like Nero means it will be easy to read in the future, and will not require installation of sundry drivers and applications. A good sanity check in this regard would be to take a disc you created to a Mac or Linux machine and see just how usable it is.
It all depends on what your backup strategy is, ours would be to archive to high quality DVD+R (4.7GB) and store them in a cool, dark, dry place. We would probably also complement that with different media types. For near-term backup we would use Tape Media or an External Hard Drive and lock it in a firesafe when not performing the backup. The speed would drastically exceed anything you could achieve with DVD-RAM.
But like we said, it depends a lot on what your backup/archive goals and strategies are.