Sleeping Good?

We have had a sleep number bed for about four years. Hubby has found his number and he has slept well for all those years. I on the other hand have not pinned down my number. I have scoliosis and believe it is harder for me because of it. I like a firm bed..He likes a soft bed.
It is said to live a long and healthy life one needs at least 6 to 8 hours of quality sleep. I only can sleep a total of 3 hours in the Sleep Number Bed. After that I am hurting bad.
We have been looking at new beds, so I can get back in my bedroom and get a healthy sleep. Places we have looked, Sleepy's. Mattress warehouse, Ikea. Brands; Serta, Beautyrest, Tempurpedics as well as others. We are looking at the Simmons beautyrest NXG 250. It is a firm but with some foam allowing some softness.
Every thing I have read lately stresses that it is very important to get the sleep one needs to reduce the stress. All these years I have been stress because of the Number bed! Whew, now I can blame it on something other than just old age,ha ha.
Do you get quality sleep? How many hours do you get? How is your Mattress?