I have used something like that, they do help a little. When I am at home working my own yard though I keep frozen hand towels in my freezer - I wet them down then wrap them around a tupperware or bottle about the size of my neck - it will freeze like that, then you just pull it open enough to get around your neck. You get a little damp as it melts, but that's all to the good from my point of view. I wear a light linen shirt with a collar, so that I can flip up the collar so that the ice doesn't directly touch my skin. Works great for me. When I want a break, I just swap out for a new one. I will even take some in a cooler with me to cut-outs. Speaking of cut outs - those fun attic jobs? There I shove ice packs in any pocket I can fit them in!
JC