After reading all the reviews, we took a chance and ordered the 12 inch king.  This mattress is perfect!  We let it sit for the full 72 hours and it popped up to height and is a great combination of plush and firm.  One corner (underneath) is a bit wonky but it doesn't affect the mattress at all.  We have the memory foam pillows as well and we're getting the best sleep.  We'll be ordering another to upgrade our guest room bed.  Highly recommend!