My husband and I are considering a permanent exterior coating rather than standard paint for our house. We have a two-story contemporary colonial sided with clapboard that is currently finished with a stain. Can we use these products over a stain? I cannot seem to find any objective reviews of the various "permanent" products out there. Are they more protective against wind-driven rain, as claimed? Also, how environmentally sound are these products? Several companies are based in Massachusetts. One is called Rhino Shield, another Lifetyme Paint. What about the "lifetime" warranties offered? What if the company goes out of business?