Two things I'd be concerned about on their website 1.) they comment on putting insulation BETWEEN the purlins and the outer walls. That would compress the insulation, making it basically worthless and 2.) it appears they advocate a poly-covered outer insulation and then if you want a second poly-covered layer on the inside for more insulation. Now you have a vapor barrier on both sides of the wall, which is an almost guarantee for mold problems.
