Hi nicca1515,
The first place I would start is post #1 here which has the basic information steps and guidelines you will need to make the best and most suitable choices for your unique needs and preferences. It will also help you avoid the worst ones such as the chain stores which sell mostly major brands (like Kingsdown) where as you mentioned the information you need about the materials in the mattress to make informed choices are not available to consumers. When a retailer tells you something is “good quality” and can’t tell you the specific quality of the materials in the mattress then it’s just empty words meant to “sell you” instead of “educate you”.
You are fortunate to live in Montreal because there are some very good local factory direct manufacturers there that make some good quality and value mattresses and are knowledgeable and transparent about what they make. You will find the ones I’m aware of in post #276 here.
The choice between different types of materials and components is a personal preference not a “better worse” choice but each type of material has better and worse quality versions so I would make sure you focus on the best quality available in your budget range regardless of the type of materials or combinations you prefer.
I have talked with Sam who is one of the owners of Novosbed and found him to be knowledgeable and open about their mattresses and they are among the better online values as well but I would always start by testing mattresses locally so you can gain some experience into the types of materials and mattress designs that work best for you and that you prefer … regardless of whether you end up buying locally or online. This would be especially important when you have specific health conditions that may put you outside of the “normal range” in terms of the type of mattress that is most suitable for you and where your own personal testing done carefully and as objectively as possible may be one of the most important parts of a mattress purchase.
Phoenix