We're one and one, here. I am 6'2 and have large shoulders, wearing a size 54 jacket. The bed gives little, so I needed to spend some time getting the pillow situation right for me (old back injury makes me a side sleeper only) as until I did my neck and shoulders hurt a lot. Never had back problems on this bed though, and now the that pillows are the right height, I am fine. As mentioned above, the bed sleeps a bit warmly as noticed by my significant other.
I like hard as a rock beds, and this one is just below that. It is sturdy enough to bend the kinks out of my back at the end of the day, but if I had it my way it would be a bit more sturdy. You sink where you apply pressure, but where there is little pressure there is little give. So for me at 285, it sinks at the pressure points of hips and shoulders. However, my feet and legs don't stay straight or sink a bit with the bed because they aren't heavy enough to do so. So, as witnessed by measuring and picture taking my my other half, on this bed I am like a tilted, lightly elevated "V" with my head on the pillow and my feet higher than normal when on my side. It is different, but as I said, I don't wake up with any back problems.
My significant other finds the bed too hard, and difficult to move around in. It is the Cloud model, and if she slept on her back as she did when trying it in the store, she would love it. She gets warm in the bed as well, and is annoyed to turn down the A/C a couple of degree to compensate for it.
Also, since she is an "active" sleeper, she finds the difficulty of moving in the matress annoying. When she sinks down, apparently she fine tunes her position, and that means you move to another spot and that has to sink down to give you the feeling you want. If it sinks and that isn't it, she has to fine tune again. Worse, the bed is too hard for her, and it makes her back hurt.
In a reversal, we got the Tempurpedic pillows and I hate them and she loves them. I felt like I put my head in a bag of wet sand and it mashed my face. Someway, she loves these pillows.
We have had the bad about six weeks now, and I would bet it is going back soon. It is quite an investment to not be completely happy with it.
For the champions of this bed (and there are indeed some rabid fanboy individuals), please understand that this is my opinion, and my opinion only. I am not attempting to represent the Tempurpedic bed in a pro or con position, only expressing my personal experience.
Robert