Hi Amity,
I would say that this is very good advice 
Assuming that the materials in a mattress you are considering are durable enough for your body type and meet the quality/durability guidelines here … the choice between different types and combinations of materials and components or different types of mattresses are more of a preference and a budget choice than a “better/worse” choice (see this article). As you mentioned it can sometimes be very surprising which type of mattress someone does best with in “real life” vs “theory” even if their body type, sleeping style, health conditions, circumstances, or preferences appear on the surface to be similar to someone else.
Phoenix