Hi MeJane,
The first place I would start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones which would generally include any of the major brands such as Serta or any mattress where you aren’t able to find out the type and quality of the materials and components inside it.
Just in case your choice is being “influenced” by consumer reports (who rates the Applause as a “best buy”) … you can see some of my thoughts about their report in post #2 here and in this topic.
Phoenix