Hi peteza,
I haven’t had the chance to try them out personally yet or talk with Latex International in detail about their graphite infused latex so my comments are more of a general nature and some of the “theory” behind it rather than from personal experience.
Graphite is a “semi metal” and heat conductive so it would improve the temperature regulation of the latex. It’s also very strong and a graphite reinforced polymer such as latex can improve the properties and strength of the raw material it’s added to and also affect the compression modulus of the foam so it would allow for softer latex that still had the ability to “firm up” and be more supportive and more durable. Of course it would also add to the cost of the latex.
The new PLB Prestige line also includes quilted talalay latex which gives a softer surface feel.
The softest model in the Previous lineup was the Worlds Best Bed which PLB rated as a 10 on their softness scale (with 10 being the softest) and the Prestige line varies from 7 to 10 with the Saint Honore Extra Plush being a 10.
They would have a somewhat different “feel” from the PLB natural lineup (which you felt as being softer) because of the different design and the different type of Talalay latex even though they are rated as having the same softness level.
I would also expect the graphite infused latex to be a very durable material so there would be no weak links in a mattress that used it in terms of durability.
Of course the “value” of these mattresses would depend on whether they were a significant enough improvement over other latex mattresses in terms of PPP to justify the additional cost compared to other types of Talalay latex or latex mattress designs and this would be up to each person to decide based on their personal value equation. IMO … as with any premium mattress … there would need to be a significant improvement compared to other talalay latex mattresses or other mattresses as a whole that were in lower price ranges that I could “feel” to justify the premium price and I would make sure you tested them as carefully and objectively as possible to make sure that real world performance was the basis for your choice instead of marketing or theory.
$3500 for the Worlds Best Bed would be less than PLB’s MAP pricing (minimum advertised price) and would be a “fair” cost for a 12" king size latex mattress. You will find other Talalay latex mattresses in a similar thickness that were both more and a fair bit less but of course only your own personal testing or personal experience would be able to tell you whether they were a better or worse “match” in terms of PPP. I would be somewhat cautious with very soft latex mattresses (or any style of mattress) which for some people may be too soft for good alignment, particulary if they are back or stomach sleepers or as in your case heavier body types. Post #32 here also has some sources for PLB mattresses that will ship across the country that you can call and talk to about their pricing and use as a “value reference”.
The tutorial post here has the basic information, steps, and guidelines I would suggest using when you are looking for a new mattress and can help you make the most suitable choices … and know how to avoid the worst ones. I would also be cautious about testing a mattress based only on “showroom feel” or “subjective comfort” which may have lower odds of success than random chance alone (see this study) and I would encourage you to test a mattress as carefully and objectively as possible using the testing guidelines in the tutorial post.
Post #3 here also has more information and links that may be useful for those in higher weight ranges.
If you let me know your city or zip code I’d also be happy to let you know of any of the better options or possibilities I’m aware of in your area. The tutorial post also has a link to some of the members here that sell latex mattresses online with a wide range of prices, styles, and options that may also be worth considering or that you could also use as a “value reference”.
Phoenix