First night sleeping on our new Beautyrest Black Hybrid LX Class was the best night of sleep in years!  My husband is a restless sleeper and none of his movements could be felt on my side of the bed.   Very comfortable and the medium support is not too soft or too hard.  It has not been warm enough to see how well the cooling technology works.  It is an inch thicker than our old mattress and all of the sheets still fit perfectly.  Highly recommend this mattress for restful sleep.