Hi again jason_555,
OK … on to some of the other points and questions that you raised in your post.
Latex … assuming it is a good quality latex … can certainly be a great material and it has a combination of properties that can make it an excellent choice that has many advantaqes over other materials. There’s more about this in the pros and cons of latex here. Like other materials though … the devil is in the details of the specifics of the layers and the other components that make up the mattress and in how they interact with your particular body type and sleeping style how well they meet your needs and preferences. Like other materials … latex is a broad category of material and there are many choices available in terms of type of latex, layer thickness, layer softness/firmness, and in the other components of a “latex” mattress or latex hybrid. There is no single mattress in other words that “defines” a latex mattress (just like traditional innerspring or memory foam mattresses are both a very broad category) and there is a huge range of possibilities within each category. Everything depends on the combination of materials and each person’s needs and preferences. If the “strengths” or “feel” of latex are not important or even desirable for a particular individual … then no matter how “good” latex may be it may not be the best choice for a particular person. In these cases it may work better in combination with other materials or some may even want to avoid it completely.
Without knowing the specific layers of a mattress (from a spec sheet, cutaway, or online description) it’s not really possible to use these as a guideline for another mattress. Of course your own personal testing on each of them (especially with the help of an “expert” who can help you translate your experience into meaningful or more objective terms and who can also give you a sense of how each specific mattress may meet your needs and preferences in the long term) should give you a clear sense of which of these would work best for you in terms of pressure relief and alignment and knowing the layers can help predict the other qualities of the mattress in terms of preferences that may not be as obvious in a showroom (such as durability and climate and temperature control). Knowing the quality specs of each mattress will also give you a better way to make meaningful comparisons with other mattresses in terms of their relative value.
Stearns & Foster for example mostly uses much lower quality synthetic Dunlop latex and most of them also have a lotof polyfoam in the upper layers of the mattress which can become the “weak link” of the mattress. This can often lead to people believing that the issues that happen with their mattress are caused by “latex” (because they were told it was a latex mattress) when in reality it is usually about the other lower quality materials that are used.
Diamond makes some high quality mattresses and they use premium materials in the surface layers (such as higher density memory foam or latex) especially in their “direct contact” models. This use of these premium materials in the top layers of the mattress means that the layers that are the most subject to repeated compression and mechanical stress are the most durable and not as likely to be the “weak link” of the mattress … unlike Stearns & Foster. Eve here though … it’s important to know the layers that are in the mattress to make meaningful comparisons with other mattresses in terms of value (such as with the PLB mattresses which have “known” specs).
Eco-flex is a “word” for polyfoam. Some of the newer types of polyfoam and memory foam made by many foam manufacturers have replaced a small percentage of the petrochemicals used to make them (specifically the polyols) with alternative polyols that are made from plant oils. While the percentage is usually small (under 20%) and the polyols are only one of the two main chemicals used to make polyfoam or memory foam … it is at least a step in a “greener’ direction … although these types of polyfoam are still just polyfoam. Knowing the density of any polyfoam used in a mattress is still important to predict durability and any “weak link” in your mattress or to make meaningful comparisons with other mattresses. Polyfoam … plant based or otherwise … is a much lower cost material than latex and while they are both “fast response” materials … latex is a higher quality choice but of course also more expensive. This means that if you are comparing two mattresses that both use say 3” of latex in the comfort layers and then one has polyfoam in the support core (such as the Diamond Peace) and one uses latex in the support core (such as the various PLB models) … it would be reasonable to expect the Diamond to be less than the PLB in order to have the same “value”.
The durability of the comfort layers is the most important part of the durability of the mattress as a while and while a latex core can add significantly to the performance and feel of a mattress … it is also true that for most people (not all) … the most significant part of the “feel” of a mattress will come from the comfort layers. This generally means that if a “compromise” is needed to reduce the cost of an “all latex” mattress and someone likes the feel and performance of sleeping on latex … that replacing the latex support layers with either an innerspring or a high quality polyfoam is often the best way to go to reduce the cost.
This may or may not be true and the best way to know would be to use the expertise and guidance of any online manufacturers you are considering. The members of this site that specialize in online and “telephone” sales are listed in post #21 here. In some cases … a “split layering” can be very valuable but your testing and specific combinations of body types and sleeping positions may also indicate that you could each do well on the same layering in spite of your differences. For example … a heavier person may "go through "the top two layers more in certain construction and they may need a firmer support core for support. The lighter part of the couple on the other hand may only “go through” the top layer and for them the middle layer may be the most significant pare of their “support system”. Each layer of a mattress can play a different role for different people in other words. Split layering though is certainly a great option to have available for those who may need and prefer it. Conversations with the manufacturer of each mattress you are considering along with good information about your stats, needs, and preferences, good questions, and any specific feedback you can provide about your local testing will help them to help you make the best possible choices out of the options they offer.
The best part is that these conversations can all be done from the comfort of your home and don’t involve travelling from store to store :).
Just in case you haven’t seen it … there is a list in post #2 here of some of the better options in the San Jose area that I’m aware of.
I hope this and the previous post helps. You have some great choices in the area and I would also suggest that you make sure you include Bay Bed in your research. They are one of the manufacturing members here and offer some of the best quality and value in the country.
Phoenix