totally depends on what piece--some quiet, some medium, some very loud. As above, obsidian pants are quiet. I have 2pair, I feel like the older pair fits me better, while the newer pair is "fine" but seems to have kind of a semi-skinny-jeans type fit. (34x34 jeans so also tall and skinny). My wife has a couple pair of the nylon pants that, while they arent hard-shell loud, are loud as hell compared to my wool pants. I wont own a pair for this reason since I have other good options and most of my WT hunting involves getting close. She also has a uncompahgre hoody that is sort of halfway between quiet and hard-shell-loud--it's better than hard-face nylon, but it's not what I would call "tree stand hunting on a calm day quiet".
I have a pair of their super heavy whitetail bibs--sactuary 2.0 I think--they are massively bulky, way too big to carry in my opinion, but they are very warm and yes, they are quiet enough for tree-stand type hunting within spitting distance of a deer. I think legit quiet for treestand hunting apparel that is very warm and also packs small is near impossible to find--have yet to find anything in this category from any manufacturer.
I also have a uninsulated catalyst jacket that I like. To me this is a good, versatile layering piece I can use for a variety of types of hunting, and yes, it is quiet enough to keep me happy in the tree stand. both of the above 2 pieces probably arent quite as quiet as the fleece type clothes, but I get so covered in burrs and snowballs in the fleece that I prefer this stuff.
