Hi buying_new_bed_,
The first place I would start is post #1 here. This will arm you with the basic information you need when you are mattress shopping. It will help you avoid the worst (or “blind”) choices so you can focus on the better ones.
Unfortunately the specs they gave you are not nearly complete (which is typical of Kingsdown) and you need the density of any polyfoam or memory foam in a mattress (unless it is less than an inch or so) to make any meaningful assessments of the quality, value, or durability and weak links of this mattress. It has 4" of polyfoam in it and I would never consider a mattress like this unless I know the quality/density or all the layers. Like all foam manufacturers … Carpenter makes some very low and very high quality/density polyfoams so the foam manufacturer means very little.
Overall … this is one of the brands I would avoid and I would avoid any mattress purchase where you can’t find the quality and density of what is in it. To use an analogy … the risk of paying “real wood prices” for particle board is just too high.
This thread includes the local factory direct manufacturers in the Ottawa area where I would put my focus.
Phoenix