I PURCHASED THIS JUST B4 CHRISTMAS AND IT WAS COLD OUTSIDE WHEN IT WAS DELIVERED SO IT HAD TO WARM UP B4 WE COULD USE IT. ONCE WE SET OT UP IT WAS VERY HARD BUT ONCE WE SAT ON AND LAYED ON IT FOR AWHILE IT BEGAN TO SOFTEN UP AND IT BEGAN TO MOLD TO YOUR BODY AND WAS VERY COMFORTABLE. WE LIVE IN A COLD CLIMATE(NH) SO THROUGHOUT THE WINTER IT WOULD BE LIKE A BRICK AT NIGHT BUT WITHIN A FEW MINUTES YOU SNUGGLE RIGHT BACK IN IT IS SO COMFORTABLE. I WAS CONCERNED ABOUT THE MEMORY FOAM BEING TOO HOT, BUT THAT IS NOT THE CASE WITH THE GEL MEMORY FOAM. ALTHOUGH IT DOES GET PRETTY HOT IN NH IN THE SUMMER I HAVE CENTRAL AIR IN MY LOG HOME SO I DON'T SEE OVER HEATING EVER BEING A PROBLEM!!  THIS WAS SUCH A GR8 PURCHASE, WITHOUT HAVING TO BUY A WHOLE NEW MATTRESS AGAIN!!! NOW I CAN'T WAIT TO GO TO BED AND NOT BE  WOKEN UP WITH SORE PRESSURE POINTS LIKE HIPS. WE HAVE A KING SIZE AND IT TOTALLY STAYS IN PLACE AND REGULAR SHEETS FIT FINE!! I WILL BE PURCHASING ANOTHER FOR ANOTHER BED. 2 THUMBS UP!!