My friend bought a twin size pocketed spring 12 inch euro top icoil and I bought a full size same type of mattress.  We are both 68 years old.  My friend had neck pain every morning from Simmons Beauty Rest innerspring.  She always thought pillows were causing the problem.  Absolutely no more neck pain from sleeping on the Zinus twin.  I had stiffness and back discomfort due to ruptured back disc from 30 years ago.  I had been sleeping on a Simmons Beauty Rest innerspring.  No more back discomfort or waiting 30 minutes for stiffness to loosen up in the morning.  This is a comfortable FIRM mattress.  We both love ours and would highly recommend!  Pocketed spring is the way to go!