opinions on Tyvek vs Typar – GreenBuildingAdvisor

Both of them claim to be superior to the other. I like the longer UV rating for Typar, as it eases some of the stress of finishing in a set amount of time. Tyvek is much more permeable, but how much is actually needed? 

Tyvek claims that Typar’s surface treatment is easily damaged, after which it’s not water resistant anymore.

Cost-wise, while Tyvek is cheaper than Typar, I have access to a locally produced Typar equivalment that is cheaper than either.

I’ll be filling a double stud wall with dense packed cellulose, and the outer wall will have no sheathing, so strength and stretch resistance is an important factor. I think Typar is stronger, but I’ve also seen Tyvek claim the opposite is the case.

Should I be considering the commercial version of either?