Had a really expensive conventional bed with pillow top and memory foam. Was hot to sleep on and I woke up every morning with sore shoulders-- didn't matter which side or back I slept on.  Convinced wife to go with Sleep Number bed.  Went with the cheaper C-2 because, once you start putting foam or pillow top on it, you are right back where you started and take away the advantage of the air mattress. Very first morning after sleeping on it. no sore shoulders.  Won't be going back to conventional bed again.