I think what you have been told (about +/-) relates to the fact that -R seems to be more compatiable with standalone DVD players than +R (althought the margin is not that big).
It doesn't matter for data. If it's important info, use the best disks for your drive. If your drive is listed in our review section, you'll find a host of different disks that have been sampled with it, and the results.
"Traveling through hyperspace ain't like dusting crops, boy"