I got a line-x liner put in my new truck bed the day after I pulled it off the lot. (2004 Colorado) IT IS AWESOME!!!
It an amazingly tough material, and it has a lifetime garantee. If you ever manage to chip, scratch, it they will fix it for free. The only time I've ever managed to hurt it was when I slid a 100+ pound freshly re-surfaced clyinder head (basically a 100 pound razor blade) across the bed. The front edge caught on part of the tailgate, and it chipped off a little dime-sized piece. As promised it was fixed for free.
It's worth the investment! I don't recommend products unless I have used it, and LOVE it.