I really like a wind shirt/layer for biking in cool temps. Lightweight, takes up almost no space so it can be packed in a pocket, blocks the wind, but doesn't cause you to overheat and sweat a ton with exertion. I have a couple of different options I use for biking, but they tend to be a little on the bright/vibrant color scheme for that use.
I think the key with these types of pieces is that they provide a surprising amount of warmth for the weight, but only when you are exerting some energy and creating heat. If you are stationary they really don't have much of an insulation value to speak of so they won't replace a fleece midlayer, for example, in that regard. I can see how it would really help retain heat by blocking the wind if used in conjunction with a fleece layer, it's just not a replacement in those scenarios. I think that's why I've never used one for hunting, it would be an addition to my system, not a replacement and I'm always hesitant to add weight. I think in the right situation it could be a great fit for me, but for whatever reason I still hesitate to change up my current layering setup. I've used my rain shell as a wind block when stationary in the past, maybe on specific hunts this could replace that when I'm not expecting to get wet. It would save a bit of space and weight over the rain gear.
Let's be honest,
@mtwarden spends way more time in the backcountry than most of us, so if he feels it's a valuable piece in his gear closet, I must be missing something. This review about has me convinced to give it a try and pick up the Kifaru, at the very least I'm considering it.
