There are many factors involved in what each person needs and prefers and I think that trying to determine what is “best” for you based on theory or other people’s opinions is not as effective as personally lying (or sleeping) on mattresses with different combinations of materials to see and feel for yourself which works best for you. Regardless of which material combinations are “best” for you … I also think it’s important to use the best quality of materials possible in each budget range (which determines durability and how long a mattress will maintain its initial performance and the comfort and support which was the reason you purchased it).
There are several parts to healthier sleeping which of course can help your body recover more completely from stress and even injury and can lead to deeper and more healing sleep.
First is good alignment to keep the spine and joints in their “neutral” and least stressed position. This is primarily the function of the deeper layers of the mattress in combination with the thickness and softness of the comfort layers. Thinner comfort layers will put you closer to the support layers of the mattress which will “stop” the heavier parts from sinking in too far for best alignment. Neutral alignment and spinal decompression allows the joints and connected tissues to relax, rehydrate, and even heal.
Second is pressure relief which encourages good blood flow to the muscles and joints and outer tissues of the body. This is the function of the softer upper layers. In many cases … younger or more athletic people often prefer slightly firmer or thinner layers here which can provide more freedom of movement and a feeling of being less “in” the mattress. As we age our need for pressure relief (thicker or softer comfort layers) can often become greater.
Third is good ventilation, moisture wicking, and humidity control so that you are sleeping in a drier environment which is more temperature regulating and can help to slow down the autonomic body functions. This means that the breathability of the mattress layers and components (primarily the upper layers but to some degree the mattress as a whole) in combination with the ticking/quilting materials and the mattress protector and bedding are all important parts of your choices.
Fourth is the ability to move freely on the mattress which is an important part of healthy sleeping. Most people will (and should) change position about a dozen times or more during the course of the night which can prevent blood pooling, muscles from becoming stiff and sore, and joints and spines from becoming stiff and maintaining flexibility.
Finally the mattress materials need to have the degree of “safety” from toxins and offgassing that you are comfortable with. For some this means using more natural materials while for others it can mean using synthetic materials (often less expensive) that have some level of certification, testing, or a reasonable assurance that the materials are “safe” by the standards that are important to you or that you may be sensitive to. For most people … certifications like CertiPur (in the case of synthetic foams) or OekoTex or Eco-Institut (in the case of various types of latex) or organic certifications (in the case of fabrics or fibers) can be important.
The many variables and preferences between different people means that personally testing different types of materials is really the best way to know which combinations may work best for you and of course some research into the materials themselves can give you some idea of their durability and the type of performance you can expect over the course of time.
Beyond this … you will find different people and manufacturers who prefer the properties or “feel” of one material or combination of materials over another but which materials you choose should always be based on personal preference. Any materials in combinations that are suitable for your specific circumstances can provide the combination of comfort/pressure relief and support/alignment you may need but will do it in different ways and with different “feels”. In general terms you will find fast response foams (polyfoam and latex), slow response foams (memory foam and gel memory foam), natural and synthetic fibers, and innersprings are the primary choices you will have. There is some general information about all the different materials used in the comfort and support layers of a mattress in the overviews in the mattresses section of the site which can give you a sense of which materials may be preferable for you but in the end nothing can replace personal testing on mattresses because your own personal experience is always more valuable as a guideline than any theory or set of “specs”. Once you have a sense of the types of material combinations that you prefer … then if you do choose to make an online purchase you will have a much better idea of what you are buying and it’s benefits.
I (or anyone) can’t make these decisions for someone else except to help you know the differences between the different choices so you can weight the pros and cons of each relative to your own needs and preferences. There is absolutely no consensus even among the most knowledgeable people in the industry about the “best” material for any person or circumstances but there is consensus that no matter what materials you choose that PPP (Pressure relief, Posture and alignment, and Personal preferences) is the “best” way to choose and that higher quality materials will last longer than lower quality materials. I would personally prefer all latex for example because it has the unique quality of being both soft, supportive, and durable and many other benefits that are important to me but this would only be a benefit for someone who could feel the difference between a latex support core and a polyfoam support core and would benefit from the differences and of course whose budget allowed it or for someone who even likes the “feel” of latex in the first place (which certainly doesn’t include everyone). While this may be my preference … others who are just as knowledgeable would argue strongly for the benefits of a different choice or combination of materials or components and some may not even feel or notice the difference between them.
Of course all of this is also assuming that any mattress you purchase uses durable versions of the materials and components you prefer because if a mattress uses lower quality and less durable materials then they can soften and break down much too quickly relative to the price you paid which can result in the loss of the comfort, support, and “feel” which was the reason for your purchase in the first place. There is little value to a mattress purchase that only works well for a short time before the materials begin to soften and break down.
The bottom line is that the one thing that can help you the most is testing different types of mattresses and materials in person to see how you feel in general about the different combination of materials and types of mattresses so you are familiar with the basic types of mattresses that are available regardless of where you end up purchasing (see this article for more about the different types or categories of mattresses).
Both the Ultimate Dreams “latex hybrid” and SleepEz “all latex” mattresses would be great quality value choices (both are members here which means that I believe that they compete well with the best in the industry) but only you can decide which would be best for you based on all the parts of your “personal value equation” that are most important to you.