Hi Blagdaross,
The first overview that is suggested reading in the tutorial post is all about the two main functions of a mattress which is comfort/pressure relief and support/alignment and the testing guidelines that can help you test for comfort/pressure relief and support/alignment are in step 4 of the tutorial. There is also a list of the preferences that may be important to you in post #46 here which is also linked in the tutorial post. There is also a list of my replies to you here and the links I provided for you to read that I believed would be most relevant to your questions and circumstances which along with the information in the tutorial is much more than “just PPP”.
That’s because specific recommendations aren’t possible to make and it’s only possible to help you with “how” to choose, help you narrow down your options so you can avoid the worst choices, answer any specific questions you may have, act as a “fact check” so that you can make sure you are getting accurate information, and help you make meaningful comparisons. You are the only one that can decide on “what” to choose or who to deal with based on the guidelines that are available to you and nobody else can do this part for you because nobody else can feel what you feel on a mattress or know the criteria that are most important to you. There is more about making specific recommendations in mattress firmness/comfort levels in post #2 here and more about the different ways to choose a mattress in post #2 here which are both linked in the tutorial post as well.
Testing mattresses for suitability is only one of the three main parts of the value of a mattress purchase. The other parts of “value” are checking for the quality and durability of the materials and comparing your finalists for “value” based on all the parts of your personal value equation that are most important to you. Going to showrooms that can’t or won’t provide you with the information you need to make an informed choice is more of a waste of time than anything else unless the durability of a mattress isn’t an important issue to you. There is also more about the most important parts of the “value” of a mattress purchase in post #13 here which is also linked in the tutorial and explains why buying a mattress that may feel “great” in a showroom or when it is new but doesn’t use good quality and durable materials that will last for a reasonable length of time relative to the price you paid isn’t particulary good value.
If you have tested a mattress and it’s a good match for you then there are still two other parts involved in making a good choice (checking for durability and comparing for value).
There isn’t a specific type of mattress that I think you should get because this is a preference choice. Your part of the “job” is to find the mattresses that meet your criteria and that are suitable for your needs and preferences and again … nobody else can do this for you. Most local areas have at least some better retailers or manufacturers and suitable mattresses available but if there aren’t any good quality or value choices available locally then there are also many good online options available as well in the same or lower budget ranges than the mattress you purchased which use higher quality and more durable materials.
In the end though … it’s always up to you which parts of the guidelines you choose to read or follow and which you don’t and my only role is to make sure you have the information available that you will need to make the most suitable, the most durable, and the best value choices possible. What you do with the information or which parts you decide to follow is always up to you and if you are happy with the choice you made regardless of what I or anyone else may think then that’s all that really matters because in the end you are the one that will sleep on it and the one that will decide when you need to replace it.
I’ve been accused of lots of things but providing too little information or only providing information about PPP and nothing else is a new one to me 
Phoenix