I put Line-X on my '02 2500HD about 2 days after I bought it new. This is not a hard working truck but has never been a soccer mom grocery getter either. It's hauled 1000+ lb iron old school machine tools, AmSec safes weighing in at about 500 lbs and 900 lbs, engine long and short blocks, full size trans and iron transfer cases, 1 ton GM 4x4 axles, all sort of stuff that can really beat on a bed. I was just hosing it out a few days ago before putting on the camper shell for a fully loaded trip to rainy CO and was noticing it looks basically like the day it was put on (except for the Reese 30k 5'er/goose rails). Hasn't faded noticeably, no damage, and it's thick enough it seems to have even kept the bed from getting dented up at all. It wasn't cheap, but I would do it again without hesitation if I ever decide to buy another truck (probably only if this one is totaled). I also knew I would be running a camper shell part time, so had it done over the bed sides single layer, and extra thick (they asked?) down in the bed.
I bought a truck many years ago that had a plastic liner in it since new, but it was warped and pulling away around the sides, and it rattled. It was about 10 years old at the time, entire life in N AL, and when I took the liner out the bed looked like it had spent years in the iron belt salt. Never...