I like a firm bed, my husband likes soft. We had a sleep number bed so the sides were night and day. Both of us like this bed and neither have had issues, his back or my shoulder. We've had it for about one and a half weeks and it seems to be a keeper.
I am surprise in your website you don't recommend the use of a box spring. In my daughter's case she had a wooden bed frame and when she sat on the edge of the bed to put her shoes on or do make up the matressshrank and the wood frame hit and hurt her legs.
The mattress has been great. The buying process couldn't be easier. There is no risk with the 100 night trial and easy return process. The price is better than the competition. You can't go wrong.