I bought this because I have a houseguest that was sleeping on the original sofa mattress so I've only slept on it once and wow what a difference.  
I cannot feel the frame/metal slats under this mattress at all.  On the original sofa mattress that's all I could feel. 
I asked my houseguest could he tell the difference and he said oh yeah! And his back is no longer hurting.  
Very satisfied with this mattress.