First off the topper is not 4" it is 2" with 2" of egg crate like top however....after some getting used to my husband and I have been sleeping great! We have a good mattress that was a little to firm and this added the needed lower back support we were both needing. We would have been ok with the 2" Sumber Solutions Memory Foam Topper but reaturning the 4" would not have been worth the hasstle. If you need a new mattress and can't make the jump the 4" would be perfet! It keeps you nice and cool while sleeping and I find I have less tossing and turning durning sleep!