I have a lawn care business I run on my days off from the fire department. I spend 6 to 8 hours outdoors at a stretch, 3 to 4 days a week from March to October and I always wear a bandanna around my neck when I'm working (or hunting, camping or fishing) A couple of years ago a friend gave me a couple of these to try. He was selling them in his T-shirt shop and wanted to know if they worked.
First, yes they do absorb a lot of water and release it throughout the day. Second if you wet them and put them in the refrigerator or an ice chest they will work better at helping to keep cooler. Having said that I don't really like them. They are very heavy and bulky to me. Also out working I had no good way to re-soak them. We carry a water cooler while we work but they need to sit under the water for a while to soak it up.They get dirty and smelly after a while and you can't wash then with soap because of the water absorbing crystals inside them. I went back to wearing a bandanna and just wetting it regularly. I also use it to wet my face or wash my hands, which you can't do with the cooling scarf.
By the way I gave one to my dad and he loves it, so go figure! I guess each to his own, so try it you may like it.
Warren