They only use a 4mil vapor barrier. They use aluminum C-channel, unknown thickness (steel is stronger and steel of an equal gauge thickness is actually 15% thicker than aluminum). Their bottom material is mesh. The warranty seems good (as far as warranties go). Last time I looked there was no mention of the quality/type of vinyl they use. I do like their adjustable tie downs. Not sure where they come up with their claim of R-24 for their 6x4 cover.......maybe it's for a 4' round cover?
Personally I find their advertising rather deceptive. They talk about using an 8mil vapor barrier, but then during ordering tell you it's 2 layers of 4mil, and want an additional $29. They talk about their great drain and dry underside, but there's a $29 upcharge for that.
