We're using this as a mattress topper because our pocket coil mattress has memory foam but it's very firm.  This is a WONDERFUL addition, it gives us a layer of plush comfort on top of our existing mattress and has made a big difference in joint & back pain. The only thing to be aware of is that (I guess because it's meant for a sofa bed) it's about 6" too short for our queen mattress. Not a huge deal, we can't tell the difference when we're sleeping and it's totally worth it for the lack of joint pain when we wake up.