My husband loves them held up greatI work in Yellowstone National Park, spending 90% of my time working outdoors. I've used these in temperatures ranging from 45°F down to 0°F. Between 45° and 30° they maintain a pretty comfortable temperature no matter what you are doing. Between 30° and about 15° you have to stay pretty active to maintain the same level of comfort. Below 10° you still need to add a third layer to keep warm. They are not as worm as most long underwear, but if you are working in low temperatures,they don't get too hot. I think they would be great for hikers, joggers, or people who work quite a bit outdoors. Probably not so much if you want to sit outside when it's 20°.The cut is off / awkward. It will probably still work as intended, but it seems that the manufacturer could have been more precise in the cut and fit. If I knew about the bad sizing, I would not have spent this much money on these and would have bought basic long johns.EDIT: (Update 11.24.18) I pulled these out of storage and gave them another try. Although the size/cut is still poor in the seat, I realized another benefit to wearing them. Compression. I have been having issues with swelling in the ankles and toes due to water retention. These tactical style under armors have a reinforced calf area, which provides significant compression. Basically, I am being kept warm with the added benefit of compression socks. The very first day wearing them, the ankle and toes swelling/bloating disappeared. (There are several benefits to wearing compression socks.) So, I can keep my house thermostat set lower due to the warmth I experience from these thermal under garments and save on my heating bill. I have found added value in my under armour.I live in the Midwest and work in a hospital setting where I have to walk outside between buildings frequently. It was important for me to find pants that I could wear under my scrubs and that would be warm enough for traveling outdoors (scrubs retain no heat in the winter) but also not leave me sweating once I was inside and working face to face with patients.This product exceeded my expectations in comfort and warmth without making me too warm once I was inside. I wear these everyday in the winter now and even wore them under my suit at a winter wedding. I tried getting a pair of one of the cheaper pants offered by another brand as a second pair but they were ill-fitting, had almost a drop crotch look, and didn't have a fly. I'm definitely just forking over a bit more money for the Underarmour brand next time!They keep me pretty warm when moving around (fleece inside). I use these as a base layer. The one complaint I have is that the butt slash crotch area can feel uncomfortable occasionally. It's the seams, they move and have to be pulled a different way sometimes. Overall, they work for me and I'll keep them.Pretty small. Feel like I'm going to rip them apart when I put my feet through them.The legs are a little long for me @ 5’10 in a large. They seem to be warm if your creating body heat & have a layer to block the wind.If your standing not moving a lot they don’t really keep you warm.Nice and warm and a good base for a layering system. These seem to be more form-fitting than the corresponding top. Lost a star because they are way long! I am 5'11" and purchased the medium which seems to be a good fit except in one dimension: length. When I wear these, they are long enough for the cuffs to go under my heel kind of like stirrups. It works OK but I assume this is not the intended use.I started using Under Armour Colgear thermals back in 2010. This is one of the replacement after nearly 6 years.Although I only use them in the winter they are brilliant. They keep you warm and dry.Excelente pantalón para primera capa, queda muy apretado así que sugiero comprar una talla mayor a la que eres normalmenteTout est parfaitA bit too low rise wait for me