This topper made my mattress much more comfortable. It's nice and cool as well as comfy. The only thing I would critique is that it doesn't fully fit my King bed. It is a bit shorter on length and width. Messes with the way the sheets fit. I am still very happy with it.
Overall the experience in dealing with Tempur has been very good. The one we ordered, the sipper pull on the cooling gel came off. Could not fix it so call them and they sent a new one. The topper and cooling gel are very comfortable. My wive wants warm I want cool but she finds the topper comfortable. We have it on top of a standard height mattress, it makes putting on the bottom fitted sheet very tight.
I tried the mattress and I loved it but the price was too much for me. I decided to try the topper not expecting it would be as good as it turned out. It's not the mattress but it's a good option if you don't want to spend the big dollars on the mattress.