I can’t say enough about this top. This is one of the most versatile and comfortable tops on the market. I now own six of them. I trail run and climb all year round. When the temperature dips below 30F, I double them up. It doesn’t feel bulky wearing two layers of this top. The material is very comfortable next to the skin (it almost feels like you’re not wearing anything) and has great warm to weight ratio. The fitted look is flattering and gives an attractive silhouette of your body.

I’m a runner and climber, I run on the trail year-round and this is the jacket I wear during winter months. At 25F, I stay very warm with this jacket and just a Rho top. It blocks out most of the wind and yet it’s very breathable. The soft fleece lining is warm but not too hot. The hood protects your head and ears from the freezing wind. The shell is very water resistant, it will keep you dry in the snow but for heavy downpours, I’d wear the Alpha SV which is super waterproof and another one of my favorites. Arcteryx makes the most stylish and sleek looking performance clothes.

This is an excellent shell - one of the best, and worth every penny. It kept me completely dry during rain, snow and hail storms on Kilimanjaro and Rainier. It's also perfect for walking my dog in the rain. I now own three of them. Love the bright colors.

Despite all the claims and rave reviews, my experience with Icebreaker has been disappointing. I have tried Ignition 1/2 Zip, Olympia Zip, Bodyfit tech top, and am not impressed by any one of them, especially this one. The Ignition's material and fit are restrictive, and it’s not comfortable to wear. Icebreaker will not be my choice of clothing for active or outdoor sports. I’m sticking with synthetics for climbing or running.

A great top for cool days and a good base layer on really cold days. Very soft and warm, and the stretchy fabric moves with you. The cut is fitted and flattering. The material wicks really well and dries super fast, so you don’t get the chill.

After reading all the great reviews, I bought two Olympia zip tops to try. While the material is low bulk, it’s not as warm as the 100 fleece. I normally wear a North Face 100 weight fleece during morning run at around 40-50F, with Icebreaker, I need to wear two layers of Olympia zip tops plus a base layer to get the same warmth. I also find them too scratchy to wear next to the skin, so I always have to wear a layer underneath.
Plus it smells like wet dog when wet and takes couple days to dry. I’m sticking with the synthetics.

I own a lot of North Face and Arcteryx clothes but decided to give Icebreaker a try after reading raving reviews about “natural” materials. I have to say that my experience was disappointing. The merino wool is not itchy but is still too scratchy and uncomfortable to wear on bare skin. So I have to wear it with a base layer. Plus, this top is not warm, especially when it’s wet from the sweat. It’s a good top to wear at home by the fireplace. For active sports or aerobic activities, I’m sticking with North Face and Arc'teryx, they performed well on Mt. Kilimanjaro, Mt. Rainier, Mt. Hood...