I don't own the Sitka Kelvin Active but using google Fu they look like 2 different products. The Sitka product is a Primaloft insulated jacket using Polartec Alpha. My understanding of Polartec Alpha is a insulation that has a primary function of removing moisture/breathable. It is used for active sessions. The Kuiu Peleton series are more of a base layer garment made of 100% synthetic material, a Toray polyester material. It appears the Sitka product is a light insulating layer; the Kuiu a sweat management with a bit of insulting value. My purpose is moisture managment next to, and one layer out, from the skin.
