Recently I bought this for some future cold weather hikes we have planned. Got to try it out this weekend in 34 degree (probably colder) and rain. Like a BOSS I only had a 40 degree bag, since the low was only supposed to be 40 degrees. I would have been freezing if it wasn't for this shirt. It kept me toasty warm the entire hike, night, and morning after. I love it and really look forward to using it for our upcoming whitney and mammoth trips this summer. Well worth the money and my girlfriend says I look super hot in it. So that alone makes it worth it. Plus I noticed a few envious looks along the trail and even got a couple complements. In all seriousness this is hands down the best trail base layer Ive ever owned. Im 6ft 185 with broad shoulders and the Large fits me perfectly.
I chose this as a base layer and mid layer. Around the house I wear it when the wood stove isn't cranked up and to bed to stay warm. It fits snug all the way around and has a zippered neck which I can crank down when I get warm.I primarily bought this as a back packing top but I think only on cooler days will I be wearing this. I am going to keep it for around camp and sleeping. My patagonia cap 2's are going to be my hiking top. I will use this in lieu of a capilene 3 or 4 top. With a fleece and shell over this I am quite warm. I hope this review helps you and I would buy this product again just to get it in a different color. I bought it in yellow and the dirt/pizza stains show. I am going to opt for a darker color if I am going to be wearing this on a thru hike of the AT.