Interesting comments, Schwert.
I haven't used merino wool much.
I have one merino top that I use on aircraft and on oil-production sites where synthetics are ill-advised and/or forbidden.
The rest of the time it stays in the time-lock vault. That stuff is expensive! But gear that works is worth every penny.
BTW: I wash my synthetics (and everything else) in cool/cold water to save energy. If they are getting a little funky, I put about three drops of bleach in the wash water and that freshens them up nicely.