I love it! It's what I hoped every expensive, or not, mattress, or sleep thing would always be. It has the perfect (for me, so far) combination of firm, yet squishy. Just Perfect! It feels engineered. I can perceive the effort and thought inside of it (maybe in the voids?). This is from a guy (me) very used to dealing with highly engineered thingys of all flavors. (** that's a compliment **) It's winter now and the next real test will come on the other side of our orbit, when my '60s home's lack of a/c will be much more material to me than it is now. Right now I've got a bedding sandwich consisting of: Purple mattress/Purple white fitted sheet/Purple white top sheet/comfy soft waffle weave blanket/grandma made flannel lined quilt made of MY OWN pre 1995 retired jeans. The bed is in the lower level of my split entry mid century home. While it does feel much cooler down there (vs upstairs) in Summer, some swampy summer scorchers will come every single year, and I'll be there, hopefully for eight sweat free restful hours. When it finally does gets hot, any kind of hot, I am making a kind of rare (for me) Optimistic prediction that this mattress will perform very, very well ( Exactly how well.....we'll see...stay tuned). I came to that prediction through two methods. One: The ventilated design by it's nature Seems to indicate a natural ventilation will occur. Of course, this is a guess. but I've got some wisdom, and I am using it here. Two: Until I decided to take my old mattress and put it inside a tent out in the snow, my bedding sandwich had one other item that had been on my old metal spring mattress (how old fashioned and gross, ick). That was my trusty mattress pad heater. This thing would warm up my bed before getting in, and sometimes through the night. It's just like a super warm (but healthy, and not contagious) entity had just gotten out, warming it up for you. It's so much better than getting into a COLD bed. Brrrrrr!! Awful. Booo! Anyway I did notice it took a much higher setting on my dial (0-10) to get the same warmth. A bummer, but as long as I just had to crank it up a bit, no biggie. But.... it does tell me that the same heat (my old dial setting) isn't effecting myself (my chilliness factor) as much.... therefore those Therms must (probably) be dissipating in the voids of Purple polymer, or some such engineering/science voodoo that I now trust, that you do so well. A + Purple *** :) I will have to find a appropriate pillow. My instinct with this mattress is to have none, but I need something to keep my head pointed to the sky (back sleeper, but side curious). Rich Yaeger a honest person with honor