On my Xterra I used Rustoleum Professional spray on bedliner on the sliders and skids. Held up pretty well and blends in well when touching up. On the 4RUnner I used Duplicolor bedliner and am really disappointed with it. It is more of a rubberized finish, but scrapes off more easily. The Duplicolor finish has worn off in a way that I didn't experience with the Rustoleum Pro. Just not a durable finish and when it does wear through it peals off in larger pieces. Luckily the primer has held up really well and has stayed put.
I need to recoat them so think I'll just pull the sliders off, peal off all the loose stuff and spray over them with the Rustoleum Pro.
Keep in mind that bedliner has a rougher texture so they are harder to clean. The sliders will look like they are holding a surface film of dirt most of the time unless you scrub them with a brush. That doesn't' bother me much, though, and the durability is worth the tradeoff. Rustoleum makes a regular bedliner and a 'Professional' bedliner, and I can only vouch for the Professional version, which costs a couple more dollars a can.