Well, since the DVD-Rewriters were out to the market, I always believed that the DVD-R is the best and the stable version from all what I read over the internet and from the manuals of the drives.
I think that the DVD+R is just a format they created to grab more money from our pockets, trying to make some things work only on DVD+R discs that do not work on DVD-R and vice versa so that you buy both all the time.
Exact difference, I know nothing except the change in writing and reading formats.
Thanks,
Nader