I own 2 full sets of gear from both. I purchased the Sitka system about 1 year before the Kuiu clothing became available. I'm sure you're aware that the founder of both Sitka and Kuiu is a guy named Jason Hairston (RIP). Goretex bought him out, so he started Kuiu. The materials and clothing are great and thoroughly tested before they go on the market. I learned how valuable the Sitka clothing was when I had to hike out of a deep canyon (almost straight up) in the Vail Valley when I was elk hunting some years ago. I was soaked with sweat when I finally got back to camp, but I wasn't cold. I stripped everything off and hung it up inside the wall tent we had and fired up the stove to get warm. Within 2 hours all of my clothing was dry. While hunting this past October for mountain goat on Kodiak Island, we got hammered with rain. The Kuiu rain gear was amazing. My outfitter and guides all had Kuiu rain gear and a fair amount of Sitka gear, too. As clothing needed to be replaced, they were switching everything to Kuiu. You can't go wrong with either one. Kuiu is factory direct so there is no retail mark-up, and you get similar clothing for a less expensive price compared to Sitka.