In a couple of weeks or so I plan on buying 16 sheets of 2" XPS foam and 16 sheets of subfloor to go on top of it in my new workshop building. There are 1" rough cut boards on the floor now, and the subfloor will probably be the final floor at least for a while, unless I find a good deal on something to go over it. Right now Advantech is $81.30 (down from $91 a few weeks ago, but still high) and off-brand sheet goods that have the same characteristics are available at Lowes and Home Depot for $44.78. This would come to $716.48, or $1300.80 for Advantech. I'd rather save the $600, all other things being sort of equal-ish, but if there is a big difference in strength, longevity or surface durability I would be willing to pay more. I'll be grateful for any advice. I've never used either product before, but have been told Advantech is the best thing for this job. So far my subfloors have all been either boards or 3/4" plywood.