We have had a SNB for about 3 years. All the ads say how wonderful they are. My husband bought one because I would get up every day with a back ache. Well, I have tried and tried different numbers and have yet to wake up without a backache. I only get relief when I come down on the couch. Almost immediately, the pain is gone. Plus, it is not the warmest mattress. It is like sleeping on a piece of canvas. It is kind of stiff. Just thought I'd vent and see if anyone else had an opinion. However, our cat, Beeba loves it.