Hi anonymom,
The better options and possibilities I’m aware of in the Minneapolis area are listed in post #2 here. Original Mattress Factory is on the list and is usually among the better options in the areas where they have a store.
This depends more on the layering, the firmness of the layers, and the type of foam (memory foam, polyfoam, latex foam) in the mattress than on the brand. Different types of foam and different designs can be firmer or softer and different types of foams respond very differently from each other as well. Some tend to allow you to sink “in” the mattress more while others tend to keep you “on” the mattress more both when you are sitting on them as well as lying on them. Even in the Serta line some will do this more than others depending on the contents of the mattress. Memory foam may do this more than most because it sinks in deeper with heat and compression than other materials but it also depends on the thickness of the memory foam and what materials are underneath them. It’s more about how the materials and layers in a mattress and how they react to your body weight and position and even though a mattress isn’t designed for the more concentrated weight of sitting vs lying … it would be something that you could test for as a preference on any particular mattress that was otherwise suitable for you.
So the simple answer is sometimes yes and sometimes no and “it depends”.
Phoenix