I was always a wood snob. I never wanted to even look at or consider a composite material for a deck. As my twelve year old daughter would say, EUW. But now that I have seen it in a few projects, I have to say, it is not bad. In fact, it has a lot going for it. First of all, it is clean polyethylene, and many companies actually use recycled plastic to manufacture it. This is especially good for city rooftops and decks that have to meet the combustible material regulation which is limited to 20%. And while Ipe and Teak are gorgeous, they are becoming an endangered resource and they are considered to be combustible. Composite decking also does not get as hot in direct sun, has long shelf life and is not susceptible to mold and rot as wood is.
Have I convinced you yet? Maybe not, but I think it might be worth a gander. There are three companies that I have seen that offer this type of material: Trex.com, Plasticwood.it.com and Hanover Pavers.