Hi Hammer,
Welcome to the Mattress Forum! 
I know it can be confusing tying to select a mattress, especially with so many sites and voices telling you “what” to choose, as opposed to “how” to choose. There’s unfortunately no possible way for me to 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”, firmness, 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).
While you may not prefer to shop at a store like Mattress Firm because of the reasoning you mentioned, that would be your own personal preference (and I wouldn’t concur with the advice you were presented that the mattress industry is a scam), but the reason I generally recommend avoiding places like this is because of the products that they offer and the general lower level of quality of componentry in those products. The major brands offers at stores like this such as Sealy/Stearns & Foster, Simmons, and Serta all tend to use lower quality and less durable 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 (along with the major retailers that focus on them as well) regardless of how they may feel in a showroom 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).
There are quite a few people making good incomes running mattress review sites. I personally have no issues with anyone making a good income. The issue I have is that many of these “review” sites are really just “revenue” sites where they know little about mattress componentry, quality or materials, which is what consumers need to know. There is more information about this in post #11 here and in posts #4 and #6 here.
You’re free to do a forum search on any of the other sites you mentioned for a more accurate representation of my opinions and the facts reasoning for those opinions, but that’s not the purpose of this site. The goal of the site has always been to provide information about “how” to choose a mattress that provides the tools and information that will make the quality and value of a purchase self-evident so that each person has the knowledge and information to be able to assess the suitability, quality/durability, and value of a mattress purchase for themselves based on their own unique needs and preferences and criteria regardless of what anyone else may prefer or recommend and without having to “believe” anyone. It’s the difference between helping the members here learn “how” to choose vs telling them “what” to choose based on preferences or criteria that may not be relevant or meaningful to them or in many cases may not be in their best interests (or the difference between giving someone a fish or teaching them how to fish).
Your comment about “impartiality” has been asked on many occasions … and so it should be from time to time. The short version of the reply is in post #2 here. A longer version is in post #64 here and in post #37 here.
In addition to the first article on the front page of the site … you can read a little more about why I started the site in post #404 here and some of the history that led to it in post #4 here.
The site itself has always been transparent about the source of it’s income and it’s listed in the services link in the top menu (the one that says "how we survive)
There is also a “somewhat hidden” donation link and my comments about donations in the submenu link that I added because of many requests (see post #7 here)
There are currently 53 manufacturing or retail members of the site. This is a very small percentage of the hundreds of manufacturers and retailers that are mentioned throughout the forum in various lists around the country but these members are the sole source of income for the site. I would guess that they represent about 10% or so of the mattresses that are purchased as a result of the information in the forum and on the site. In other words I point to value or even “possibilities” wherever I find it, regardless of membership here.
One of the most important goals of the site has always been to be fact based and to promote full disclosure so that anyone can validate the information for themselves and not have to “just believe” anyone (including me). A manufacturer or retailer being endorsed here is something that is earned. I’m not in the business of selecting mattresses for people, but I instead endorse businesses and manufacturers who have the heart of a teacher and provide products using higher-quality materials. Claiming that being supported by businesses of this type tarnishes the wealth of objective information covering a broad variety of brands and topics presented here (most who are not members here) would be cynicism.
Any project which has been a 12 - 16 hour a day project for over 6 years without a day off yet of course needs an income to survive and I’m grateful that the income is now at the point where basic survival is no longer an issue … even though it took some time (over 2 years) and the emotional and financial support of family members to get there.
So it was time once again for someone to ask the question and hopefully it’s been answered for you and others who may be curious. It’s nice to see that this time it was asked in a spirit of what I hope is curiosity and a tone of respect instead of being part of a personal attack which has been the motive behind it on several previous occasions.
The answer to this is quite obvious – trust yourself. If you learn about the quality of different componentry, this will set you up for your best chance at success as far as durability goes, but aside from that, only your own careful personal testing will be the ultimate guide to telling if you like a mattress or not.
My advice would be to 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”, firmness, 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 (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
While as I mentioned earlier nobody can speak to how any specific mattress will “feel” for someone else or whether it will be a good “match” in terms of comfort, firmness, and PPP because this is too subjective and relative to different body types, sleeping positions, and individual preferences, sensitivities, and circumstances and you are the only one that can feel what you feel on a mattress … outside of PPP (which is the most important part of “value”), the next 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 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 the information listed here so you can compare the quality of the materials and components to the 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 the durability and useful life of a mattress before making any purchase.
In the end, you’re always free to take information from any source to make up your mind, and in many cases you might take a little bit from “here and there” that makes sense or resonates with you. But to answer what I think is the overall theme of your post, I’d put a lot more stock into YOU and more emphasis on learning about mattress materials. While this site is one of the best resources you’ll find for that information, whether or not you procure that information here or elsewhere is immaterial. I just recommend that you acquire that knowledge.
Phoenix