A couple of my communities have them as a standard. The product is expensive. I have never seen a comparable product warp, but it does fade.
If your back deck gets a lot of afternoon sun, I would stay away. The composite gets really hot to the touch. They have some PVC coated products out now that are fade and supposedly heat resistant. Those products go for around $50 per board.
There is a pressure treated product that is called KDAT. It's the normal ole pressure treated wood but is kiln dried after treated. One of my builders have had great success with it. You can stain or treat it right after its installed. Literally no warping.