I have the Bushwhacker bed rail caps, and they're ok. Great company, since they sent a free replacement tailgate cap that blew off in some high winds in Palm Springs. If my toolbox didn't hold them down, the side caps would be gone too. The plastic is holding up fine, but eventually the heat and cold break down the 3M tape that keeps the caps on the truck. No tape, no caps. I'll eventually get the bed sprayed, but I have the Bedrug for now. They are great too, sending me a new set of 3M tape for the tailgate as well. For about $100, you keep the rails from getting scratched and rusting. Hope this helps.
TP