We have had a Tempurpedic for a little over 10 years now.
I used to wake up with my left arm useless, hasn't happened in 10 years now. My wife swears by it for her back and hip pain. I get hot, but not to the point it bothers me much, I also like a lot of covers, it may be connected. My wife doesn't have the problem, but she throws back at least one blanket.
When the mattress is cold, it is hard and very cold. You have to lay in one place, cold, until your body heat softens the foam and you sink in a little. We always sleep with a window open in the winter. There were times when I would come home in the morning and the mattress would be like lying on a slab of concrete, but that was Montana and the temps were near 0F (+/-). It would warm up fairly quickly and I could get to sleep. The manufacturer say not to use a heating blanket or pad on the mattress, so we haven't.
The one question I have always had about this foam; how well does it stop bullets? If I were to use it for a barrier, would it stop, or slow down a bullet? The company won't give me a sample to test, maybe I can find someone getting rid of their mattress and I can chop it up. :)
The transfer of movement, or lack of, is nice. I seldom, if ever, feel my wife come to bed or get up if I am sleeping.
All in all, we are glad we went with the mattress. There have been a lot of improvements made in the bed since we bought ours, such as different models, thicknesses, etc. If we have to replace it in the next ten years or so, we will probably get another one.
bob