Well, closed cell foam is much superior to open cell in most ways. It insulates better, i.e. better R-values-6-8 per inch in some cases, and if your concerned with thickness, that means it takes less material to provide the same insulation value as more of the open-cell. And like one of the gentleman said earlier, it's stronger and provides better structural support. When I was looking into
Dallas remodeling contractors for my home, I discussed some of these issues. But I decided to go with traditional insulation, though, because a lot of these sprays contain hazardous chemicals and use HFCs as spraying agents. Although there are more that, more recently, are beginning to be made more green conscious.