Under Armour Cold Gear
Being a sports nut, I have been deluged by the Under Armour ad campaign. Being a sucker for marketing, I began to wonder how UA would work for hunting. So, I had a spare hundred bucks to blow, so I bought an olive green set of Under Armour Cold Gear compressionwear.
It is hands-down, the best cold weather undergarment I've ever used. When actively moving (carrying treestand/pack for miles) it wicks away and evaporates moisture, and you actually feel relatively dry. My old cotton thermals would stay wet.
In early archery season, I was wearing only my UA shirt bowhunting, with camo pants. As it is form fitting, you look and feel less bulky on stand, and it is warm enough to wear ALONE!
The negative: 1. Since this stuff is so tight, it actually squeezes the hair on your body, bending the hair follicles in random directions, causing them to hurt over long periods of time. It's kinda like if you wear a tight beanie for a long time, when your head gets a little sore. 2. Since it serves to evaporate sweat so rapidly, it enhances the dissipation of human scent. I needed to be a little more careful and reapply my scent killer a bit more often.
Positives: 1. Warm 2. Form fitting 3. Olive is a good enough color to wear alone in early season 4. Dry 5. Doesn't snag easily 6. Keeps ticks out (but they can still get at your head)
If you buy a set, buy one size larger than you'd normally wear, as it is REAL tight.