That Duratech stuff looks just like the pex I used for my infloor heat lines. I was thinking pex would be great for an air system. Sounds like I might rethink that. Copper would be my next choice but it is getting really expensive.
Are you anti PVC guys anti pex too? I really can't see pex having the same issues as PVC. On second thought, pex is sensetive to sunlight, so probably not the best choice. I wonder how the Duratech handles sunlight.