Hi Rmsanger,
Without knowing the specific information here … there isn’t any way to assess the quality or durability of the materials in a mattress. You can’t “feel” the quality of the materials in a mattress and lower quality and less durable materials can feel the same as higher quality and more durable materials in a showroom or when they are new … they just don’t last as long.
ILD is a “comfort spec” that is used as a measure of softness/firmness with foam materials not a “quality spec” that affects the quality of the materials. It isn’t measured in pounds per square inch so they either didn’t provide you with accurate information or you may have misunderstood what they told you.
So called “soy foam” is just polyfoam that has replaced a relatively small percentage of one of the two main chemicals used to make the polyfoam (the polyol) with a polyol that is derived from soy oil (see post #2 here). It would be closely comparable to other types of polyfoam that are the same density range.
I would need to know all the information about the specifics of the materials in any mattress to be able to make any meaningful comments about it.
If you can find out all the information I would need and post it on the forum I’d certainly be happy to make some comments about the quality of the materials or the mattress as a whole.
There is also more about the most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful comparisons between mattresses.
Phoenix