Hi Alyseal,
Yes … the choice of materials is a personal preference although I would always make sure that it’s a good quality and more durable version of that material because every material has lower quality and less durable versions and higher quality and more durable versions.
Tempurpedic uses firmer polyfoam as a support material under their memory foam comfort layers. In general … polyfoam that is firm enough to be used as a support layer wouldn’t be soft enough to relieve pressure points without adding a topper to replace the comfort layers that are used in the mattress when it’s the other way around.
The balance between “comfort/pressure relief” and “support/alignment” is the most important part of any mattress purchase for everyone and is the reason that careful and objective testing is important. What works well for one person may be completely unsuitable for someone else to sleep on (see mattress firmness/comfort levels in post #2 here).
I would avoid the tendency to study the information in the tutorial post like you would a textbook and read it like you would a good book. The most effective way to buy a mattress is to know “just enough” that you can recognize the experts that already know what you would otherwise need to learn. Not enough information can lead to some poor quality choices but too much information can also lead to information overwhelm and “paralysis by analysis” which can also lead to poor choices when you put theory ahead of your own personal experience.
The key is to choose a mattress that is a good match for you in terms of PPP (and theory won’t be able to tell you this) and then make sure it uses good quality and durable materials that are suitable for your budget range (the lowest budgets won’t have the highest quality of materials).
If you follow the steps in the tutorial post one by one you will bypass the information overload and have much better odds of success than trying to learn enough to become an expert yourself.
If you have read the information in the tutorial post then it’s probably time to decide where to do some testing and if you let me know your city or zip code I’d 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 links to some of the better online choices I’m aware of if you are comfortable with an online purchase and wish to include them as one of your options.
Phoenix