BACK SAVER!!!Perfect level of firmness! Not too soft, not too hard.  I have some degeneration of the lower lumbar spine, so back pain is pretty much a constant for me.  Our old mattress was starting to get "dips" and sunk in too much and my back pain was getting worse.  This mattress has been a life changer!  I wake up in the morning with so much LESS back and body pain!  Highly recommend!