I should start by saying that I use wool Ibex briefs for colder weather hiking, running, skiing, etc., but 1) I find wool underwear too hot and uncomfortable for warmer weather hiking 2) the Ibex underwear has one flaw, which they may have addressed in their latest seamless underwear (I got mine 2 years ago) – the leg openings had no elastic and thus the briefs tend to ride up your bum. Not fun in warm weather.
So after ignoring synthetics briefs for a while, which synthetic briefs are most comfortable and least odor-holding for warmer weather backpacking? I have found that mesh-style polyester briefs (or shirts for that matter) will hold odor like the devil – smooth style garments hold odor less. That's because odor-causing bacteria love the extra surface area offered by mesh weaves.
Does the new Patagonia Cocona odor-control work in their polyester and capilene garments? Is there another synthetic treatment that works better? I've found that X-static (embedded silver fibers) barely works, at least compared to high quality merino wool.
I'm not odor-shy – I just can't stand how some of my synthetic garments stink so bad after just a short use, whereas my wool garments can go days. I literally wear a thin wool running top 3-4 days in a row with no serious odor.

