I wasn’t sure that this would fit on top of my pillowtop mattress, I also have a memory foam topper.  My wife insisted it would fit so I humored her in trying to put it on, to my surprise, it actually fit!  It isn’t loud and crinkly like sleeping on plastic bags and it almost seems as if my mattress is fluffier. I like being able to have something that zips everything up so I don’t have to fuss with corners popping off the edge of the mattress all the time.  I really love how the memory foam topper is now protected as well, it was always a hassle cleaning spills off of it and what not.  Happy with this product and would recommend!