Like some of the others on this site, we have had a miserable experience with Restonic. After only 8 months of using the mattress, we have craters in the mattress and back pain. After calling Restonic headquarters, we were directed to a manufacturer in N.C., called Alliance, and told that they would handle the warranty. (Restonic apparently subcontracts their work out...) We were required to fill out and return a form and asked to perform a 'string test', wherein one pulls a string across the mattress and if the sagging area... read full review »