When the dust settles and if all is equal (compatibility wise). Which do you think the mainstream computer user will chose? DVD-R DL, with mindless burn and play.....or DVD+R DL, with toggle bit, burn and play?
The average person doesn't know what a USB port is, let alone bitsetting DVD media. (average person = big sales = more manufacturers = more competition = lower pricing).
Time will be the judge. But we definitely need a competition jolt to help lower media prices.