OS- the merino has the itch out...the wool fiber that you grew up with have small "scales" that are removed through various processes. Those are the buggerg that make the itch as they irritate the skin...

Terry-been running wool and plastics in baselayer forms for years...pros and cons to both. Plastic a bit more durable but then one has the funky fragrance and "oil". Wool is pretty much funk free, a different kind of warmth (drier IMHO), but the fiber is more fragile...and the merino garments are a bit more pricey.

So ergo the wool power query....they are one of the few that use a blend of plastics and wool in their base layers. I like the wool but the durability, costs, overall greenest are taking away from that dry warmth looking for an improvement  or maybe I am just splitting hairs so to speak....just saying.