Hi wright1107,
As you’ve read in my comments about airbeds in general … one of the “flaws” with airbeds is that air displaces and like an on/off switch it’s either fully compressed or not compressed at all and it can tend to displace and sag in the areas of greatest weight. Unlike foam and innersprings … outside of the flexibility of the air chambers themselves it doesn’t have any progressive resistance as you sink into it more deeply. Most airbeds also use firmness adjustments to change the comfort level of the mattress but changing the firmness of the support system isn’t as effective a way to change the comfort level of a mattress as changing the comfort layers themselves because by choosing a softer setting for the comfort level of an airbed you are actually softening the support component of the mattress which can lead to exchanging comfort issues for support issues.
Having said that … the design of the Natural Form with its separate air chambers or helical air cells, self adjusting technology, and valve limiters can offset some of the inherent weaknesses of an airbed to some degree IMO but this is only a matter of “degree” and would still be relative to other materials since the air chambers that are the support system of the mattress still relies on air to provide the support. While it may be a better or more effective design than many other airbeds … the real question is whether it is “better for you” compared to other types of mattress designs or support materials that are available to you.
I’m not clear on the density of the memory foam or the specifics of each layer since your first comment mentions 3 lb (which is lower than I would normally consider) and your second comment mentions 4 lbs and also mentions two foam layers and I’m not sure of the specifics of each one. If you could provide the type, thickness, and density of each layer I would be able to make more meaningful comments. The guidelines I would use for foam quality/density are in this post.
A firm 1.8 lb polyfoam is a suitable density and wouldn’t normally be a weak link in the mattress.
You may very well be correct that you are overpaying for a mattress that doesn’t have a significant advantage in terms of PPP or durability compared to other types of mattresses that are available to you but again your own experience and the quality of the sleep you experience during the trial period is the only way to assess this. It’s not likely that the helix cores would depress by an inch unless they were deflating and defective or had a hole in them and the foam would be a more likely source of any impressions or any softening in the mattress. I would also be cautious about warranties because foam softening or “virtual impressions” aren’t covered by a warranty and a warranty has little to do with the useful life of a mattress (see post #174 here). While the helix cores may adjust “automatically”, innersprings and foam cores do as well and the real issue is not whether they adjust but “how” they adjust and whether the “automatic adjustments” in any mattress effectively keep you in alignment in all your sleeping positions.
In terms of durability … I would want to confirm the quality/density of the foam in the comfort layers but outside of that you would need to be comfortable with the higher probability that mechanical systems are more likely to develop issues over time than other types of mattress components or materials. In most cases … defects in good quality foam materials (such as latex) will tend to show up early in the life of a mattress (generally in the first year or so) and after that they tend to be very consistent but mechanical systems can break and develop problems at any time so I would also take into account the higher risk and any costs and “effort” involved in replacing any components that break down over time.
Choosing a mattress that is a good match for you in terms of PPP would either be based on your own personal testing and experience or if that isn’t possible then the alternative would be to make a choice based on a more detailed conversation with a manufacturer (see mattress firmness/comfort levels in post #2 here). Progressive, differential, or zoned designs are just concepts behind mattress designs that can help people understand the different types of mattress construction but these wouldn’t be nearly as important as your own personal experience in terms of PPP or if you are making an online purchase then a more detailed conversation with a manufacturer along with the options you have after a purchase to either customize, exchange, or return a mattress if it’s not the best “match” for you. These types of generic design concepts aren’t something that would normally be part of a mattress choice (outside of possibly zoning if you have a more “challenging” body type) because most consumers wouldn’t likely have have the knowledge, experience or reference points to use these types of more complex and nuanced information and concepts as a meaningful part of making a specific purchase decision anyway and putting undue importance on this type of information over the options you have after a purchase can easily lead to information overload and a tendency to choose a mattress based on information or specs that may be very complex and not particularly relevant in “real life”.
All of this though is based on “theory” and personal experience always “trumps” theory when it comes to PPP and how well a mattress works in “real life” for any individual because the most important part of the “value” of a mattress purchase is how well you sleep on it (see post #13 here). No matter what anyone else (including me) may think of airbeds in general, they can still work very well for some people, but the only way to know this would be your own personal sleeping experience so you can decide whether the quality of your sleep on your Natural Form mattress justifies the higher cost and risk compared to other mattresses that you have tried or that are available to you. These are always “best judgement” decisions that would be based on all the parts of your personal value equation that are most important to you.
Phoenix