Hi pattycake,
The major brands certainly tend to use low quality/density materials in their mattresses and in general terms smaller manufacturers like Gold Bond do tend to tend to use higher quality/density materials than the major brands (and your mattress is also two sided which would be a more durable choice than a one sided mattress that uses the same materials) but when you are buying a specific mattress rather than talking in more general terms then the only way to assess the quality and durability of the specific mattress you are considering would be by knowing the quality and durability of the materials inside it.
I would always be very cautious about brand shopping in general because you are buying a specific mattress not the brand and most manufacturers have access to the same or similar components and materials. Many manufacturers make a wide range of mattresses that can vary from lower quality and less durable materials to higher quality and more durable materials in a wide range of prices. The name of the manufacturer on the label or the price of the mattress won’t tell you anything about whether a specific mattress is suitable for you in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your Personal preferences) or whether there are any lower quality materials or weak links in the design that would affect the durability and useful life of the mattress. There is more about the risks of brand shopping in post #5 here and post #12 here.
Phoenix