Hi jmf0t,
It wouldn’t for me no. Innersprings have many “specs” (see this article and post #10 here) and only comparing them by one or two is mostly meaningless. The most meaningful comparison between innersprings would probably be their total weight (the amount of steel they use which would be a main part of their cost) but this also wouldn’t take into account the many differences in how different types of innersprings feel and perform and it’s not a “spec” that any manufacturer provides. Innersprings are also not usually the weak link of a mattress which is normally the upper layers. Like you though it seems odd to me that the basic specs of an innerspring are a “manufacturers secret” and I would at least want to know the type of innerspring they used.
I’m not so sure I would call it “fine” but he is correct that lower density foam in thinner layers has less effect on durability than the same type/quality of foam in thicker layers. The layers above any lower quality foam layers will also affect and extend their durability to differing degrees if they absorb some of the compression forces. If the top layers of a mattress contain more than about an “inch or so” of lower density polyfoam then I would be cautious so this is just over the amount that I would normally prefer to see in the foam layer that is closest to the top of the mattress if the mattress was one sided. If the mattress is two sided then this would be a much more durable design. you can read more about the factors involved in the durability of a mattress in post #4 here.
Latex would certainly be more durable than polyfoam in the top layers but it would also change how the mattress feels and performs so I would want to test it with the specific layering and materials you were considering to make sure it was suitable for your specific needs and preferences before buying it (and some manufacturers won’t make a custom design unless you agree to buy it first).
This would be a much more durable construction because latex in a top layer is more durable than polyfoam. There is no such thing as HR memory foam (HR means high resilience and all memory foam is low resilience) and they may have been wanting to say HD (meaning high density) but this isn’t a number and different people have different ideas of what they consider as HD in memory foam. It’s only an inch which is within the guidelines I normally suggest is OK for unknown materials in a quilting layer but it would still be nice to know its density. This mattress doesn’t have a “weak link” that I would cause me any concern although I would still want to make value comparisons with other similar mattresses (latex/innerspring hybrids) because the cost may be on the high side (although they would probably still compare well with most mainstream mattresses).
A good manufacturer will also provide you with meaningful durability information that isn’t so much focused on “selling you” as it is on “educating you” and they would know that 1.5 lb polyfoam is not nearly as durable as latex but that it is also less costly which is why you see it in mattresses that are in lower budget ranges.
Phoenix