Hi jaide,
ILD means “indentation load deflection” and it is a common measure of the relative softness or firmness of different foam materials. There is more about ILD in post #6 here. I would also keep in mind that it’s only one of the specs that can affect the softness/firmness of a material or a mattress that uses it (see post #4 here).
In most cases it’s best to avoid trying to choose a mattress based on “comfort specs” or “theory” unless you have a great deal of knowledge and experience in what they mean in your own personal experience and how the different specs and different combinations of materials can affect the feel and performance of a mattress. The “quality/durability” specs (see here) are much more important to know.
Unfortunately only you can feel what you feel on a mattress and there are far to many unknowns, variables, and personal preferences involved for anyone to be able to predict with any certainty which mattress or combination of materials would be the best match for you in terms of PPP (Posture and alignment, Pressure relief, or Personal preferences) based on specs (either yours or a mattress) or “theory at a distance” (see mattress firmness/comfort levels in post #2 here).
There is more about the different ways to choose a mattress (either locally or online) in post #2 here that can help you minimize the risks involved with each of them without having to know this type of complex (and often confusing) information.
Both Brooklyn Bedding and Dreamfoam are completely transparent about the materials they use in their mattresses and they will provide you with reliable information about the materials in any of their mattresses if you ask them (and you will need to talk with them about your comfort choices anyway) but the information in my previous reply includes the differences in quality and durability between the support cores in all three of these mattresses.
Phoenix