Friend of mine set the whole outfitter tent with three other guys gear in it on fire the last week of bow season trying to dry his synthetic out hung over a wood stove. The worse part is that they were 9 hours by horse from the trail head. The shine is because it reflects rather light like plastic rather than absorbing light like fur or hair.
Merino wool makes excellent long underwear. It's not much good around anything that pokes, scrapes, pulls, bucks or binds for very long. For underwear it's tough to beat as it doesn't stink or suck the oil out of your skin like poly. You can wear one set for a week if you have a good outdoor woven woolen over it.