Hi huanshowen,
There are many subtleties and competing “influences” to mattress design and how different types of layering interact but the way to cut through all of them is to trust what you feel. ILD numbers really aren’t really important at all when you are testing mattresses locally. If you feel a mattress is firm, then for you it is firm … depending on what you are referring to when you call something firm (see post #15 here about the different types or “species” of firmness/softness)
Soft solid elastomeric gels are a very durable material and with it’s durability if anything it would extend the life of the layers below it because it would absorb and shield them from some of the mechanical compression that causes them to soften and degrade.
While it would be great if someone shared their experience with this mattress … anything they were to say about its comfort or support would probably have little relevance to someone else where the same mattress may feel and perform very differently. It would also take many years before someone’s feedback could say much more about the durability of the mattress than knowing about the materials will already tell you. A forum search on Technogel (you can just click this) will bring up some more feedback about them (and some good descriptions of the pillows) but given the generally questionable value of the mattresses and that it may only really be attractive to a very small percentage of people … it may be a while before a member here decides to buy one
Phoenix