Is it Kerry that's the PLUS R proponent? And I think he bases this preference on "newer standard, newer manufacturing equipment, perhaps higher materiel quality? (Not that any manufacturer would be forthright about any of these issues.)
The MINUS R proponents might claim "Older DVD-Video Players were first using the MINUS R standards, so MINUS R disks have a chance for greater compatibility."
It then appears to be a "Better Burning Quality vs. More Compatible Playback" but if a consumer asks, "How many of the world's oldest DVD players will I use?" then the MINUS faction probably loses ground.
I am unconvinced by 'better materiel' arguments especially since manufacturing of disks has, for the most part, become the sole focus of cost-cutting and using cheapest materials possible. If there's an issue of Better, I think the appropriate follow-up question is "... than what?"
Longevity is the important factor for me, and I'm unsure if I will believe any argument that claims one standard is absolutely, certainly the longer-lasting of the two. I barely put stock in tests that claim to reasonably predict a 5-10-30 year lifespan of these items.