Hi Da,
There are too many variables between different mattresses and different people for anyone to provide specific recommendations. There also isn’t a “formula” that you can plug in height/weight/sleeping position information that will come up with the “perfect” mattress. In general this will involve talking with various manufacturers or retailers on the phone and asking the questions and finding out the options that they would suggest for you. My goal is to help the forum members here to eliminate the worst choices and to help them narrow down their final options to choices between “good and good” and from that point onwards to “get out of the way” so that their conversations with the various manufacturers and retailers that are in their “final list” can help them determine their own “value equation” and which choice suits them best in terms of their needs and preferences.
At that point there is really no “best and worst” but only choices that are best for YOU and nobody else can determine this for you. If your final choices are all good quality and value then the tradeoffs between the objective, subjective, and intangible differences between your final choices are the best way to make your final decision.
If you are looking for an online purchase … I would first decide on the materials you are most interested in and then talk with the manufacturers on the list in post #21 here which offer these materials and let your conversations and their guidance help you make the best choice based on the criteria that are most important to you (along the lines of post #2 here).
Phoenix