Hi skoobz,
The first of these (and I’m assuming you mean the Tempurpedic Cloud supreme) is a high quality mattress but there are many others who use similar layering and quality of materials that are far better value. Tempurpedic is a good quality but poor value mattress and the goal is always to have both quality and value.
The iComfort on the other hand is much lower quality but also poor value. If you go to post #11 here you will see an analysis of the materials they use. They are less costly than Tempurpedic but also use lower quality materials.
These guidelines will help you avoid most of the worst choices when you are mattress shopping and hopefully keep you away from major brands and mass market outlets where the expertise, quality and value is much worse than many other options you have.
The most important step for any consumer shopping for mattresses is to first find the better factory direct outlets or better sleep shops in your area. They will have the experience and expertise to give you the guidance you need to make the best choices for your needs (pressure relief and posture/alignment) and your preferences in a mattress along with having much higher quality/value mattresses to choose from. Once you’ve found the better outlets … then it’s time to start looking for a mattress. This way you will connect with the “experts” who can truly help you rather than needing to become one yourself or being forced to trust the advice of salespeople in most mainstream outlets who are often better trained in marketing than they are in mattresses and how to fit the many different types to the needs and preferences of each individual or couple.
If you let me know the city or zip you live I’d be happy to let you know of any better outlets I’m aware of that are near you.
Phoenix