I think this mattress is very comfortable.  We bought a king size one for the master bedroom and a queen size one for the guest bedroom.  Both of them began to expand immediately upon opening.  They were completely off gassed in 24 hours and the smell was not too bad at all during that time.  We slept in the king sized one after 24 hours.  It was comfortable and felt fully expanded.  We let the queen sized one continue expanding for 48 hours and then slept in it to try it out.  I did not notice any difference between the two.  I would definitely buy another one.