After deciding to look for a new mattress (our existing one was 10 years old, and we both suffer from lower back pain), we took a wander around the showrooms.... We made the 'mistake' of trying a Tempur fairly early in our 'lie-to-try' test, and nothing else compared..... We've always had pocket sprung mattresses in the past, and found those more comfortable, but after trying v costly pocket sprung mattresses, the Tempur was still far more comfortable. Far and away more comfy than the other (cheaper!) memory foam / hybrid mattresses too, and the difference was quite marked.
Takes a little getting used to the sensation of the foam moving around as you settle into position, but worth it. I used to wake up with back stiffness every morning, but not had it since getting this.
Big benefit in not needing to turn the mattress too - these things are heavy, so a good thing to avoid.
Cooltouch makes a definite difference for heat control too.
Although costly, we figured that we spend 25-30% of our lives on this, and if it can save on the bad back, it's def worth it.