I just went through a couple of very hot humid days (almost 90 on the east coast) and my fanny stayed cool. However
It serves the purpose for now.  Bought a breakfast nook and the seats edges are somewhat sharp and uncomfortable on the back of the legs.  The cooling-gel portion does work!  I just went through a couple of very hot humid days (almost 90 on the east coast) and my fanny stayed cool.  However, it is not a comfortable cushion.  It actually hurts my bottom after a short while so I have to get up alot (which might not be a really bad thing).  It's just not as soft and cushy as I thought it might be.. Maybe I am just too heavy and for that reason they get the 4th star instead of just 3.  The carrying case also looks cheap and it difficult to get the cushion in and out of it.
Rating: 4 stars