This is my first merino jersey. I’m 5’10” 190lbs and I got size medium. It fits snug as I like. My 5’10 150lb son tried it on and it was loose on the torso, but he’s usually in size small cycling kit.
I like the colors. The back pockets are synthetic, but it’s merino against your skin all around. The pockets are smartly reinforced. The only thing I don’t like is the oversized front zipper. The merino blend fabric is great - just what I was looking for.