I installed TimberTech (tongue and groove version) on our front porch 5 years. It was WAY expensive and terribly heavy...however, it was one of the best decisions I made in our remodel project. I'm kind of a slob and tend to track lots of "stuff" around. Spring and fall...2 gallons of bleach in a hand sprayer, soak it well, wait 20 minutes or so and hose it off. VOILA...brand new looking, all over again. It's also absolutely arrow straight, and stays that way.
It does fade, to a very light gray/brown color, but it works incredibly for us. ABSOLUTELY no sag, give or anything on 16" treated 2x8 joists. I also considered it on my floating dock, but the price and weight were a bit much.
BTW..for anyone considering using EBTys on treated 2x6 decking, better reconsider. Without a fastener in the middle, the boards will tend to warp upwards (cup) in the middle. I'd at least use one (SS) screw in the middle of each board at each joist. Been doing construction long enough to know that this will be necessary.
In a lifetime, the average driver will honk 15,250 times. My wife figures I'm due to die any day now...