If you put a composite deck next to a redwood deck, 10 out of 10 people will tell you the wood looks, smells, feels better. Composite will most likely cost more, perform worse, you must sell it? How bout hot calm days and the smell of oil (voc's) from your petro based material, or how spongy it gets between joists when it is hot, even on 12" centers. Composites add the weight of a couple people to the deck because it is so heavy, if you dont add more joist than normal, the whole deck feels spongy, there is no strength whatsoever in that stuff. Can you even run it at diagonals? Do you have to use 6-8" centers if you do? Composite decking would be a great product, if it were 1/10 the cost, it is in the same league as vinyl siding, but vinyl siding is cheap.