Pillowtops do and will sag after a while and that is across all manufacturers. It just comes with the territory and I would avoid them at all cost. I ended up buying a Latex mattress last year and I am very happy with it. I got the plush without pillowtop and if it is too firm, you can always buy another latex topper and put it on top of the mattress. This way you can always make a firmer mattress softer is that is your preference. Latex mattresses last a long time and do not attract mites.