Hi Kj72,
Welcome to the Mattress Forum!.
I’m not sure what you’ve read and what you haven’t since you found the site and you have many questions and some assumptions that need to be clarified so this reply will include a fair bit of reading.
Just in case you haven’t read it yet … the first place I would start your research is the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones.
Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on all the parts of your personal value equation that are most important to you.
As you mentioned latex and memory foam are completely different materials with very different properties but the choice between them is a preference and budget choice rather than a “better/worse” choice. Some people prefer the “feel” and performance of latex and some people prefer memory foam. There is more about some of the general differences between them in post #2 here but as you mentioned the most reliable way to know which types of materials or mattresses you tend to prefer will be based on your own testing or personal experience.
Assuming that the materials in a mattress you are considering are durable enough for your body type and meet the quality/durability guidelines here relative to your weight range … the choice between different types and combinations of materials and components or different types of mattresses are also more of a preference and a budget choice than a “better/worse” choice (see this article).
All foam materials will get softer over time but if they are good quality and durable materials (such as latex or higher density memory foam or polyfoam) then the softening process will be less and happen over a longer period of time than it will with lower quality/density materials. As long as the mattress you purchase isn’t “on the edge” of being too soft for you so that even a very small amount of foam softening would take you outside of the comfort/support range that is suitable for you then you should be fine (see post #2 here).
I would keep in mind that mattress warranties only cover manufacturing defects and they don’t cover the gradual (or more rapid in the case of lower quality comfort layers) loss of comfort and support that comes from foam softening that is the main reason that most people will need to replace their mattress. In other words warranties have little to do with the durability or useful life of a mattress or how long it may be until you need to replace it. If there is an actual defect in the materials it will usually show up early in the life of the mattress but knowing the quality and durability of the materials in your mattress is always a much more reliable way to assess the durability and useful life of a mattress than the length of a warranty. There is more about mattress warranties in post #174 here.
There is more detailed information about the many variables that can affect the durability and useful life of a mattress relative to different people in post #4 here.
Latex can be either natural or synthetic or a blend of both. For example the latex in most of the Pure Latex Bliss mattresses are a blend of 30% natural rubber and 70% synthetic rubber. There is more about the different types and blends of latex in post #6 here.
That would certainly be possible but your own careful testing or personal experience will be the only way to know for certain. Some people sleep very well on latex and some sleep very well on memory foam. It would also depend on the specific type of memory foam because different formulations of memory foam have different properties (see post #9 here and post #8 here) and on the design of the mattress (some mattresses use thinner layers of memory foam mixed in with other more resilient materials either above or below the memory foam which would be less motion restricting).
There is more information in post #9 here about the different ways that one mattress can “match” or “approximate” another one. Every layer and component in a mattress (including the cover and any quilting materials) will affect the feel and performance of every other layer and component and the mattress “as a whole” so unless you are able to find another mattress that uses exactly the same type of materials, components, cover, layer thicknesses, layer firmnesses, and overall design (which would be very unlikely) then there really isn’t a reliable way to match one mattress to another one in terms of “comfort”, firmness, and PPP based on the specifications of the mattresses (even assuming that you can find out all the specifications you would need for both mattresses you are comparing in the first place).
Mattress manufacturers generally try to differentiate their mattress from the mattresses made by other manufacturers and don’t normally try to “match” another mattress that is made by a different manufacturer so unless a manufacturer specifically says in their description of a mattress that one of their mattresses in the same general category is specifically designed to “match” or “approximate” another one in terms of firmness or “feel” and PPP and/or they are very familiar with both mattresses and can provide reliable guidance about how they compare based on the “averages” of a larger group of people that have compared them (different people may have very different opinions about how two mattresses compare) … the only reliable way to know for certain how two mattresses would compare for you in terms of how they “feel” or in terms of firmness or PPP (regardless of anyone else’s opinions of how they compare which may be different from your own) would be based on your own careful testing or actual sleeping experience on both of them.
The mattress shopping tutorial also includes several links to lists of many of the better online options I’m aware of (in the optional online step) that include many different types and categories of mattresses in a wide range of budgets, firmness levels, and with different return/exchange policies that may also be well worth considering.
The online memory foam list in the tutorial includes several manufacturer and retailers that make memory foam mattresses that are designed to be reasonable approximations of many of the Tempurpedic mattresses.
The mattress shopping tutorial also includes a link to a list of the members here that sell mattresses online and many of them sell latex and latex hybrid mattresses that use different types and blends of latex that have a wide range of different designs, options, features, return and exchange policies, and prices and some of them also sell (or can custom build) latex mattresses that would be reasonable approximations of some of the Pure Latex Bliss mattresses as well.
If you are open to an online purchase and when you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
All the major brands (such as Sealy/Stearns & Foster, Simmons, and Serta) tend to use lower quality materials in their mattresses than most of their smaller competitors that will tend to soften or break down prematurely relative to the price you pay which is why I would generally suggest avoiding all of them completely (and the major retailers that focus on them) along with any mattress where you aren’t able to find out the type and quality/durability of the materials inside it (see the guidelines here along with post #3 here and post #12 here and post #404 here).
I would also read the comments in post #2 here about trying to “approximate” a major brand mattress such as the Serta and when you are considering a mattress where you aren’t able to find out the type and quality of the materials inside it then unfortunately even the time you spend testing these mattresses is mostly wasted.
While I can certainly help with “how” to choose … I don’t make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort” or PPP or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
I or some of the more knowledgeable members of the site can help you to narrow down your options, help you focus on better quality/value choices that are available to you either locally or online, help you identify any lower quality materials or weak links in a mattress, act as a fact check, answer many of the specific questions you may have along the way that don’t involve what you will “feel” on a mattress, and help with “how” to choose but only you can decide which specific mattress, manufacturer, or combination of materials is “best for you” regardless of the name of the manufacturer on the label or whether anyone else (including me) would have the same criteria or circumstances or would make the same choice.
There are some very general guidelines about what to expect in different budget ranges in this article. Your budget would be on the low side for most all latex mattresses but you are in a budget range where you would certainly be able to find some latex/polyfoam hybrids and some good quality memory foam mattresses as well. Some of the better lower budget online options I’m aware of are also listed at the end of post #4 here and the other online lists it links to.
If you let me know your city or zip code I’d also be happy to let you know about any of the better options or possibilities I’m aware of in your area that may be worth considering as well.
Phoenix