Merino - devoured by moths, disintegrates at friction points, not great at wicking.
Merino/synthetic blend - all qualities of merino, more moth-proof, plus longevity and better wicking.
Lambswool/synthetic blend - as per merino/synthetic, itchiness disappears after a couple of washes, 10-25% of the price of merino.
From my experience:
Merino - devoured by moths, disintegrates at friction points, not great at wicking.
Merino/synthetic blend - all qualities of merino, more moth-proof, plus longevity and better wicking.
Lambswool/synthetic blend - as per merino/synthetic, itchiness disappears after a couple of washes, 10-25% of the price of merino.