For most of my testing period I used this mattress pad on top of the . This mattress falls at a 6 out of 10 on the firmness scale, where 10 is the most firm. With the eLuxurySupply mattress pad the mattress felt more like a 5 out of 10 on the firmness scale. Typically, I would sink 1-2″ into the Brentwood mattress. After placing the pad on top, I experienced a lessening of the sharpness of the contour / hug, but increased softness and pressure relief. The mattress pad dissipated some of the foam hug by dispersing weight more evenly.
Of course, not every mattress will have this reaction. The design and age of your mattress will create a different feel and overall experience. However, you can always count on increased softness. I would expect the eLuxurySupply bamboo mattress pad topper to increase softness of any mattress by around 15%.