I just finished using these screws on a DIY deck using composite lumber. I drove about 1200 of these.
Pros:
- No predrilling -- that's a real timesaver.
- No "mushroom" bumps that usually happen with composite material (the reverse threads at the head pull the material down with the head). Many of the fasteners pulled themselves into the material so well, it almost looks self-healing.
- Fast insertion.
Cons:
- The reverse threads prevent you from pulling these screws out again once they're set. If you mess up (I did a few times) you can't unscrew them. I had to pound them out with a hammer or pry the boards apart -- not pretty.
- More $$$, but you'd expect that.
Overall: These screws did a great job holding my composite deck together. They pull themselves in tightly and there are no bumps on the composite boards. They are climatek treated, so I expect they'll last just as long as my beautiful new composite deck.