I purchased Underarmor when I was deployed to Cuba. With the 100+ degree days, every day, and with all of the equipment we carried, I could get 3-4 days out of a T shirt. A regular cotton shirt, I got a day, tops. The sweat, once it dried on cotton, made the shirt stiff & abrasive. And, it smelled something HORRIBLE. The UA shirts remained pliable, didnt chafe, and didnt smell. My vote would be for UA, as I personally love the stuff.