Hi Tomcat,
The support of a mattress is relative to the firmness of the base foam and the thickness and softness of the comfort layers, your body type and sleeping positions, your weight distribution, how evenly you sink into a mattress, and whether a specific mattress maintains good spinal alignment in all your sleeping positions (allows some parts of your body to sink in more deeply and “stops” other parts of your body from sinking in too far). It is not related to the quality/density or durability of the material.
The best way to assess the support/alignment or the comfort/pressure relief of a mattress would be based on either your own personal experience on the mattress (or a very similar mattress) or based on more detailed conversations with a manufacturer or retailer (see mattress firmness/comfort levels in post #2 here). This has to do with the suitability of a mattress design not the quality of the materials. In this case … they compare this mattress to the Tempurpedic Cloud Luxe in terms of it’s softness (they have said that it’s just a bit firmer) so you could use your personal testing on the Cloud Luxe along with more detailed conversations with Dreamfoam to decide whether this mattress would be a good “match” for you in terms of PPP. There is also more about how one mattress can “match” another one in post #9 here that you can use as reference in your conversations.
The quality/density of the materials and the useful life of a mattress on the other hand is a very different issue than support/alignment or comfort/pressure relief.
You are on the border of the weight range where I would begin to be more cautious with the use of 4 lb memory foam in the top layer of a mattress or lower density base foams (regardless of the manufacturer) because it will be less durable than higher density memory foam and will soften more quickly than higher density memory foams even though it may “feel” more comfortable initially because of the softness of the materials. Because of the overall softness of the mattress it may also be more risky for higher weight ranges in terms of providing good alignment in all your sleeping positions because higher weight ranges may need firmer comfort and support layers than the “average” (their heavier parts will sink into the mattress more deeply).
I would make sure that you have done some careful and objective testing on the Tempurpedic Cloud Luxe (which has a similar design with 2.75" of 4 lb memory foam over 2" of 5.3 lb memory foam and a 1.5 lb base layer) to make sure that it’s a good “match” for you in terms of PPP and then you can talk with them and decide if the mattress is a good match for you and is “worth” the tradeoff compared to a mattress that uses higher density materials but may be more costly.
It’s certainly a great quality/value choice in it’s budget range but that doesn’t necessarily mean that it would be the most suitable choice for you so I would use your local testing on a similar mattress and your more detailed conversations with them as the basis for your decision.
Phoenix