I'm planning to change my Mattress. Anyone please advice me.

My mattress was really frustrating. I’m planning to change my mattress. But the main challenge in front of me is the selection. What all criteria I should consider? I was searching for a good mattress type. Then I found Stearns and foster beds are really good. The next search was for a good brand. I was searching based on reviews and comments and last I got a good mattress brand with an immense collection of Stearns and foster beds. The reviews are quite impressive. Had anyone purchased this brand’s mattress? Your advice will really help me.