My TimberTech deck is 12 years old and still looks like new. I have never used any product other than Corte Clean because it was recommended by the manufacturer. Our deck (1,000 sq. ft in multiple levels) is prone to black mold stains, especially under areas that are tree shaded, but the Corte Clean gets them right out. I use the product in spring and fall, doing an initial "spot cleaning" in the worst areas, then apply a diluted solution which I do not rinse off. I am also happy with the support the company provides- personal attention is there if needed. I would recommend ordering the product from the website because it seems fresher and works faster than what I bought in the deck store, even though it was within the expiration date.