My opinion is 80's are better for dirt performance. 100's are better for paved performance. Dirt performance is 4x more important than paved performance, so I weight that ratio accordingly meaning if you're 80/20 paved/dirt then you are right on the fence (80*1 = 20*4). If you're realistic and know it's more like 90/10, then the argument is no brainer 100 series (90*1 > 10*4).
Adjust the "dirt weight variable" and paved/dirt ratio to your liking, and viola there's your next truck.