After purchasing 3 different brands of mattresses we finally found the one that fits our style. Hybrids, medium firm foam, all after 100 days or sooner sagged in the middle, like falling into a pothole. Back aches and hip soreness were the result. 
First time purchasing from Milliard and wow in 24 hours we received the mattress. Opened up the package and after four hours the mattress expanded to 10 inches. The first night was tough as our bodies had to get use to the firmness. After a couple of days we both slept well and immediately fell in love with our mattress. If you find it to firm just add a topper.