Hi KevKanos,
I would be cautious about both the Tempurpedic Cloud Luxe and the Dreamfoam 13" gel memory foam mattress in your weight range because they are both the softest memory foam mattresses they make and because both of them use more than “about an inch or so” of 4 lb memory foam.
While there is no way to quantify how long any mattress will last for a specific person or predict exactly when you will decide to replace it because it is no longer suitable or comfortable for you (this is the only real measure of durability or the useful life of a mattress that really matters) because there are too many unknowns and variables involved that are unique to each person … if a mattress is well inside a suitable comfort/support range and isn’t close to the edge of being too soft when it is new (see post #2 here) and you have confirmed that it meets the minimum quality/durability specs that are suggested in the guidelines then it would be reasonable to expect a useful lifetime in the range of 7 - 10 years and with higher quality and more durable materials like latex or higher density memory foam or polyfoam (in the comfort layers especially) it would likely be in the higher end of the range or even longer and the chances that you would have additional “bonus time” would be higher as well.
If a mattress uses lower quality/density materials than the minimums in the guidelines relative to your weight range then it would be reasonable to expect that it would last you less than this … and depending on the many variables involved in some cases it could be significantly less.
It would also be reasonable to expect that any mattress won’t last as long for someone in your weight range as it will for someone that is lighter.
There is also more detailed information about the many variables that can affect the durability and useful life of a mattress in post #4 here.
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 (Posture and alignment, Pressure relief, and your Personal preferences) 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 accurate 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’m assuming that you’ve read the mattress shopping tutorial (which is the first place to start your research) but 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 (Posture and alignment, Pressure relief, and Personal preferences) 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 (including the price of course and the options you have available after a purchase to exchange or return the mattress if your choice doesn’t turn out as well as you hoped for … especially if you can’t test the mattress before a purchase).
While I can’t speak to how any mattress will “feel” for someone else because this is too subjective and relative to different body types, sleeping positions, and individual preferences, sensitivities, and circumstances … outside of PPP the most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the quality/durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it regardless of the name of the manufacturer on the label (or how a mattress feels in a showroom or when it is relatively new) so I would always make sure that you find out information listed here so you can compare the materials and components to the quality/durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to your weight range.
If you are looking at online options then the mattress shopping tutorial includes several links to lists of the better online options I’m aware of (in the optional online step) that include many different types and categories of mattresses (including memory foam) in a wide range of budgets, firmness levels, and return/exchange policies that would be well worth considering although I would make sure that any mattresses you are considering uses mainly materials that are suitable for your weight range which would include 2 lb or higher polyfoam, 5 lb or higher memory foam, or any type or blend of latex (outside of a total of “about an inch or so” of lower quality/density materials).
If you are also interested in local options then if you let me know your city or zip code I’d be happy to let you know about the better options or possibilities I’m aware of in your area as well.
I or some of the more knowledgeable members of the site can certainly 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 that you may be considering, 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” based on all the parts of your personal value equation that are most important to you.
Phoenix