Hi lora,
The first place I would start your research is post #1 here which has all the basic information, steps, and guidelines you will need to make the best possible choice … and avoid the worst ones (including Serta). It also includes testing guidelines that can help you test a mattress for pressure relief, alignment and your personal preferences. Testing a mattress for “comfort” alone (which is very subjective) to make your choice is among the worst ways to choose a mattress and has lower odds of making the most suitable choice than random chance alone (see this study).
You can read a little more about hotel mattresses and why they often feel different at home than in the hotel in post #3 here and the other posts it links to but they are also among the worst choices in terms of quality and value and you also won’t be able to find out the quality of the materials they use in their mattresses. A mattress is only as good as its construction and the quality of the materials inside it and I would completely avoid any manufacturer who won’t tell consumers the quality of the materials they use in their mattresses.
You can read a little more about “matching” another mattress in post #9 here but since they don’t disclose anything about the specifics of what is in the mattress there is no way to “match” it except with your own personal testing and trying to “match” a memory of a subjective 'feeling" isn’t an accurate way to match one mattress to another.
I would follow the guidelines and focus on smaller manufacturers and sleep shops that can “educate” you about their mattresses instead of “selling” you and provide you with all the information you need to make an informed buying decision.
Once you get to step 3 … if you let me know your city or zip code I’d be happy to let you know about some of the better options and possibilities I’m aware of in your area.
Phoenix