Hi Indylady18,
You can see my thoughts about individual component layers vs glued layers in post #2 here. More individual layers that can be re-arranged or exchanged allow for more options and greater levels of customization both before and after a purchase (with a layer exchange) and it also allows you to replace a single layer if one softens or breaks down before the others (which would usually be the top layer) or if your needs and preferences change down the road without having to replace the entire mattress.
If you know the type and blend of latex inside a mattress and the type of cover and the quilting that is used then you can make more meaningful comparisons with other mattresses. There is more about the different types and blends of latex in post #6 here. Once you know the specifics of two mattresses you are comparing then which one has “better value” or is “better for you” would depend on the parts of your personal value equation that are most important to you.
All of the manufacturers you are considering use good quality latex materials and good quality covers and there are no “weak links” in any of them but there are some significant differences between them in their designs, options, types of latex they offer, and the exchange or return policies they offer as well as their cost.
If they use a suitable quilted cover or with an unquilted there is a single solid layer of latex then you won’t notice the split no … although of course you would notice the transition from one firmness level to another on each side (which is the reason for the split layering in the first place). There is more about this in post #2 here.
Phoenix