I bought one of these after a recommendation from this site. However, once you factor in Florida summer temps with their humidity, it's just not worth it. You're only going to cool the air about 3 degrees. Not enough in my opinion, so I sent it back.
I think it's a great little product and if you were going somewhere with warm temps but low humidity it would be ideal. We just don't experience that combination enough to make it worth while.
I bought a couple mister fans and going to go the wet bandanna route and hope that'll be enough to keep us cool. I also picked up a couple of those squeeze and shake instant cool packs for just in case.