My husband and I purchased this mattress for a California king water bed frame. The mattress we had been using was a softer mattress so the firmness of this one took a little getting use to. We've slept on it for about a week now and I will say we are completely satisfied with it. The first couple of nights (while the foam was still expanding) the bed was extremely firm. We have the layers in the order for maximum firmness. We have a feather topper on it and the firmness is perfect for us now that it has fully expanded. It also fits our bed frame perfectly even though it was made to go into an RV unit. Deep pocketed king sheets as well as California King sheets fit this mattress perfectly.The mattress does seem to hold heat and 'sleeps very warm'. My husband is loving this fact, I sleep warm so to help adjust we have adjusted the thermostat and are using sheets that are cooler. The feather topper also helps cut down on some of the heat transfer. The mattress takes perfect shape to your body while sleeping but not to a point where it is hard to roll over or get up. Also, since sleeping on this mattress the lower back and shoulder pain I had been experiencing has completely gone away. Another positive to this mattress is you can move or get up without worrying about disturbing your spouse/partner. You can barely feel the other person moving!We have told several of our friends about this product, and should the need arise again in the future we will purchase either the same product or a similar product. I was trying to think of any negatives to this mattress and the only thing I can come up with, is since we started sleeping on it, we seem to want to linger in bed longer in the mornings before getting up!