Hi ssabolovich,
The first place to start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the bet possible choice … for you.
Your own careful and objective testing using the testing guidelines in the tutorial post is the only effective way to answer this because each person may be different and a mattress that works well for one person in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) may not work well at all for someone else (even if they are the same weight).
I would keep in mind that if you are connecting “support” with “firmness” then you can easily end up making a poor choice because a mattress that is too firm can be just as non supportive and allow your spine to sag just as easily as a mattress that it too soft (because it may only provide support under the protruding hips and shoulders but you may not sink into it enough to provide support under the more recessed parts of your body such as the lumbar curve on your back or your waist on your side). In other words, spinal alignment in all your sleeping positions is always the goal which means that a mattress needs to be firm enough in the deeper layers to “stop” the heavier parts of your body from sinking in too much but also needs to have comfort layers that are soft and thick enough in the comfort layers to provide good pressure relief and to fill in the more recessed parts of your body so they are “supported” as well.
The PLB mattresses certainly use good quality and durable materials (blended Talalay latex) but the quality of the materials has little to do with how well the design of a mattress will work for you when you sleep on it.
There is also more information in post #3 here and the posts it links to that may be helpful for those in higher weight ranges but again … following the steps in the tutorial post along with your own testing is the most reliable way to know which mattress is the best choice for you in terms of PPP and the other parts of your personal value equation that are most important to you.
Phoenix