Personally I have never liked anything around my neck and I have used the coolers in Iraq. But i would have to say I do like the concept of wrists wraps better.
http://www.polarproducts.com/polarsh...Wraps-p291.htm
I have used a lot of submersion on the wrists in water baths during hot weather and to me the effects last longer then on the head or neck. (my observation on myself)
Just remember these products work better in dry hot environments where you have evaporation on your side.