Vapor barriers will make you wet and sticky. The only place I've used them, and the only place I'm likely to ever use them in the future, is on my feet. Bunny Boots use a vapor barrier technology to sandwich a scarily thin layer of insulation between two rubber layers, keeping outside wetness out and inside wetness in, and the insulation completely dry. They work extremely well. Down to about -20F sedentary or -40 or -50 active. Your feet will get wet and wrinkled, and you MUST change socks and dry your feet several times a day, or risk major foot problems. If you wish, though, you can just wear cotton socks to help soak up all that sweat, and wipe the boots out with a rag when you change socks and dry your feet.
I would not be willing to sleep in vapor barrier if I had any other means of keeping myself warm enough. I would not be willing to wear vapor barrier garments on any other part of my body unless I had absilutely no alternative. The rest of my body just doesn't do quite as well with being soaking wet.
Stryver
