Hi Summersday4u,
The first place to begin when you are looking for new mattress is post #1 here. This has all the information, steps, and guidelines you will need t make the best possible choices … and avoid all the ones you are mentioning … even as a reference point.
There are only 3 ways to “match” another mattress which you can read about in post #2 here. Since Serta doesn’t disclose all the information you would need about what is in their mattress and there is no other manufacturer that builds a mattress that is designed to “duplicate” it … the only way would be based on how it feels to you but since “feel” is subjective and not particularly “accurate” in the long term … this would only be somewhat accurate if you were testing another mattress side by side in real time in the same store and not particularly accurate at all if there was a period of hours or days in between testing each mattress.
I would suggest having a more standardized set of “targets” that you can evaluate all mattresses against rather than using another mattress as your “target” … particularly when there is no way to know the specifics about what is inside it.
Phoenix