Hi anna.sorin,
I just realized because of the previous poster that I hadn’t answered your post. Sometimes when I am replying to one post another one is added to a thread and I miss it. My apologies.
You’ve probably already read this (because you already know that I normally recommend local factory direct outlets or better sleep shops) but just in case and for the sake of others who may read this … these guidelines will help you avoid most of the worst choices when you are shopping for a mattress.
Post #48 here has and analysis and some thoughts about the Sealy Optimum line and the reasons I would avoid it.
The overviews in the mattresses section of the site also has lots of information about different mattress materials that are used in the various parts of a mattress and “fitting” a mattress to each person’s needs and preferences that may be worth scanning so you can ask better questions and will also help you to know when the answers you receive are more about marketing or are meant to help educate and guide you into making better choices.
Post #6 here has a list of some of the better possibilities in the Raleigh area.
Again … sorry to take so long with this reply.
Phoenix