Im 6-2+ medium build. The L was sort of snug and this heightened the itch factor I think. That being said, it was stink free after several days straight and layers good under just my Marmot Precip in subfreezing windy weather for sweatfree hiking. The comfort and stink control far outweighed the minor itch.

People aren't lying when they tell you that merino wool doesn't hold odor. This top breathes well, wicks sweat, and dries quickly when wet, and is cotton soft. Ultra-light. And doesn't smell. Not super warm, but they sell heavier weight tops if you want warmth. As it is, this has worked ideally for me in temps to the mid-50s under just a wind jacket so long as I'm moving some. Lower if I'm moving more. I haven't had any durability issues in 4 months and have worn it regularly for morning runs, day hikes and multi-day backpacking trips with heavy-ish packs. It's a base layer, i.e. always under something, so I don't know how it would respond to snags or abrasion. It holds up pretty well to washing, though you don't have to do it often as it never stinks, just gets dirty. I have two, and one I've been less careful with, allowing it to end up in a washing machine rather than hand washing, and it has started to pill ever so slightly and feels a tad bit rougher than the almost exclusively hand washed one. Either way, it's been 4 months and neither shows any major signs of wear. My only complaint is that even though the seams are flat, they still will chafe a tiny bit under a heavier pack (over 15 lbs, say). With a daypack, this hasn't been an issue. I'll probably get something with a raglan sleeve for backpacking, but it will definitely be made of merino wool.

Very comfortable and I really liked the microweight for higher output activities and warmer days, but it was made for someone much taller and more slender than my 44-short torso.

So many people like the merino wool base layers, that I decided to check it out. In my opinion, Lightweight Patagonia Capilene is far superior. It is somewhat lighter than microweight. The big advantage is it wears much better. The microweight merino wool is far too delicate of an item.

We travel to Europe frequently and often go with carry-on luggage. There is simply nothing that beats Smartwool items for wearing comfort and light-weight packing!

This is a great base layer! Its very warm, comfortable, very odor resistant, and wicks moisture very well. I wouldn't say its better than Patagonias Capilene or any other well built base layer but I would say its exceptionally good for cold weather expedition. I've worn it several times for days at a time in harsh cold weather environments and its always served me well. My only complaint is I wish the sleeves were longer. I'm 6'4" & 185 Ibs and I ordered an XL. It fits well but the sleeves are shorter than I like. If it had thumb loops it would be legendary! Regardless, I highly recommend adding it to your base layer collection.