I have used a two part Epoxy-Plus Marine Epoxy from Clark Craft on over 8 pickup beds over the last 12 years, and as far as im concerned you cant beat it. Builds to a tough and high gloss, and i mean it is strong stuff. Put it on all sides of the wood to seal good, and in about 7 years you might need to light sand and put on another coat. The ones i have done have never had to be recoated, but they have been parked in a garage when not being driven. Have never had one discolor yet. I have built over 20 cedar strip canoes using this same product and it really shows the beauty of the wood. Everyone will tell you they have the best product, but its up to you to decide.