I have the whipcord wool shirt (made from the same material as the pants) from Cabela's, and I like it so much, I'm probably going to order the pants and another shirt. From what I understand, the SW100 finish is more like a coating which covers the fibers and allow them to slide against each other and prevent them from interlocking with each other. It is this interlocking of fibers that gives wool it's reputation for shrinking. So far I don't see any downside to it. I suppose it could wear off, but after reading the long term reviews on the Cabelas site, it doesn't sound like it would

I don't have any experience with the Filsons, if there was a place around here that sells them, I probably would have bought one.