I read all the reviews but was still a little skeptical until the first night sleeping on this topper. WOW! It is a MIRACLE TOPPER. I do not know if the 2" or 4" would have been as wonderful but the 3" is "just right"! As far as it taking hours to come back to shape after unpacking, that was not the case. It came back to shape almost immediately. The odor was very mild. It also was not hot. We covered ours with a mattress pad and fitted sheet and it was perfect. I cannot say enough positive about this topper. We have a Select Comfort bed that we purchased years ago that I was never happy with. We also had an expensive pillow top mattress that was never comfortable either. We always woke up with aches and pains. We decided to put this topper on top of the Select Comfort mattress after airing it up firmly to provide a good support for the topper. It worked perfectly. Best nights sleep in years. Another plus is, while sleeping with your spouse, you will not disturb each other. It seemed that we were always rolling towards each other. Now it is like having your own personal sleep space. Your size and weight will not affect each other. I will never purchase another conventional mattress again. I would not recommend the topper if you have a wavy mattress as it will conform to those waves and dips but if you have a firm mattress, this is the answer to receive a great nights sleep. Another helpful hint is to purchase a california king if you have a queen, turn it 90 degrees, and cut one side to fit. We laid ours out on our hard wood floor, used a 1x2 for a straight edge, and cut it with a utility knife. If you purchase the king it won't be long enough as a queen and king bed are the same length. The cal. king worked perfectly. I hope you enjoy your topper as much as we have enjoyed ours.