Hi izzi81,
The mattress you listed has over 5" of “questionable” materials plus some fiber in the comfort layers as well. Worse yet it’s convoluted which is less durable than a solid layer of foam. This is exactly the type of construction that I would avoid unless you are able to find out the density/quality of the foam layers.
You would be much better off with a mattress that minimized the use of these types of materials and then adding a high quality topper where you can control the quality of the top layers of your sleeping system.
Some of the other mattresses you’ve mentioned earlier in this thread would be much better choices in terms of minimizing questionable or lower quality layers.
Natural and synthetic fibers will compress more than good quality foam because they are less resilient and will compress more over time. They are good for more “point specific” relief of pressure points and for improving the breathability of the surface of the mattress but they are not as good at overall pressure relief as foam materials. there is more about wool toppers in post #3 here and more about some of the different fibers in toppers in post #10 here. If you are having foam “sinking” issues then a firmer foam may be the answer. Memory foam also has more of an “in the mattress” feel than faster response foams like polyfoam and latex which have a more “on the mattress” feel. The type of foam doesn’t matter and is really a personal preference. No matter which type you prefer though choosing higher quality will make sure it doesn’t soften or break down too quickly. 4 lbs or greater with memory foam, 1.8 lbs or higher for polyfoam (1.5 lbs used with caution), or any type of latex (which is all a durable material) are all good choices.
Many of them still are … it depends on the type of innerspring and on the design of the mattress. You probably didn’t try some of the “more springy” ones (I’m guessing you mean the types of innersprings that have a helical wire such as Bonnel coils or Offset coils).
Phoenix