Hi mattress_n00b,
It’s not so much that it would be too hard but it would be ineffective. A mattress is only as good as the quality of it’s construction and the materials it contains and “brand” shopping is one of the worst ways to buy a mattress.
In general there are two “brand groups” that are frequently mentioned on the site.
One of these are “major brands” and I generally recommend avoiding them because they tend to use lower quality materials in every price point or worse yet don’t even disclose what is in their mattresses.
the other group of “brands” I mention is what is commonly called “off brands”. These are typically smaller independent or local manufacturers that are sold either factory direct or through better sleep shops. While not all of these are great … as a group they will have the best quality and value available and if you focus on materials in the mattress then it is much easier to recognize good quality and value.
There are a series of steps listed in post #1 here which along with the information it links to will greatly increase your odds of finding the best quality and value mattress and most importantly finding a mattress that is suitable for your unique needs and preferences.
Focusing on materials and better, more knowledgeable and better value sources will lead to much better choices than focusing on brands.
There is no formula that can take weight, body type, or sleeping position specs and “translate” them into the best possible mattress for you without at least some personal testing that can give you some reference points but there are some guidelines that are in the overviews (linked in the post I mentioned) which can give you some general information that will help you ask better questions and be in a better position to ignore the marketing information you will be exposed to and know when someone really has more knowledge and experience about what makes a better quality mattress and how to choose the one that is best for you.
A local purchase where you can personally test a mattress for PPP (Pressure relief, Posture and alignment, and Personal preferences) is the most accurate way to make sure a mattress is suitable for you.
You can read more about Essentia in this thread and more in this thread which would probably be enough for most people to pass them by. As you mentioned their marketing is questionable at best and their value is not great IMO.
There are some great choices in the San Francisco Bay area and you will find them listed in post #2 here with the knowledge and experience to give you some very good guidance in terms of the type of mattress that you would need and prefer and that have much better value than the mattresses you mentioned.
Hope this helps but if you have questions along the way feel free to post them here.
Phoenix