Got a very good deal price wise on the 12" king size mattress.  Arrived pretty quickly with free shipping.  We let it sit in opened setting for about 65 hours and it never expanded to a full 12". It got to 10" after about 48 hours but that is all.  It is a medium firmness and slept good but does not have the edge support we had hoped for even though it state it has edge support.  Especially for the price we paid of $299.00 for king size mattress, I feel we got a pretty good deal!!