Hi kryton619,
Both of the top two layers are good quality and durable materials but unfortunately I can’t make any comments about the durability or useful life of a mattress or whether there are any weak links in the mattress “as a whole” or make any meaningful comparisons with other mattresses you are considering without knowing the density of the support core as well.
As I mentioned Springwall told me in the past that they would provide this information to their customers and it’s disappointing to see that they aren’t providing this any longer.
Having said that … I called their general manager to confirm whether they were no longer providing this information to consumers (manufacturers will often provide information to their retailers through their reps that they won’t provide directly to consumers) and he said this was correct but after a longer conversation he was able to confirm that the density of the base layer was at least 1.8 lb density (less than this could create durability issues with roll packing a mattress) so if you are in more average weight ranges (lower 200’s or less) and the polyfoam base layer is 1.8 lb density or higher (I would suggest 2 lb density or higher if you are in higher weight ranges) then there would be no lower quality materials or weak links that would be a cause for concern.
Costco has a great return policy so you can test the mattress in your bedroom instead of a showroom to find out whether it will be a good “match” for you in terms of PPP with little risk (outside of the time you spend sleeping on it and/or returning it if it doesn’t turn out to be as suitable for you to sleep on as you hoped for) so if it compares well to any other finalists you are considering (either locally or online) in terms of the quality and durability of the materials and all the other parts of your personal value equation that are important to you (including the price of course) then it would certainly be worth considering.
Phoenix