Pth..
Optical has and still sucks for backup. They're SLOW, unreliable, and have a low shelf life compared to hard drives. Total pain in the ass. The only reason to use DVD is to make DVD movies and only DVD-R is compatible, DVD+R is not.
As for replacing VHS I would bet my money on DVRs, not crummy optical media. A DVD only holds 90 mins unless you pay through the balls for a DVD-9 burner! What's the point of that?
The only point to DVD+R was the DVD+R *only* burners were cheaper due to licensing. Having a burner which supports both the useful and useless format and costs more money is less than pointless.