I'm a synthetic fan. I know I'm in the minority but I find them warmer, lighter and faster drying than wool. They can make a stink but my body chemistry seems to work well with the treated synthetics. I've worn my base layers for over a week with no major problems. Yes, I've owned hign quality merino (Icebreaker, Smartwool) for years, and I do love merino sox, but I'll hang on to my synthetic base layers which are basically dry when they come out of the spin cycle in my washing machine.