When it comes to finding the perfect mattress, I am very fussy.  Beds that are too firm hurt my joints and beds that are soft cause my back to hurt. The Serta Perfect Sleeper Pacific Peace Medium is truly a perfect combination of firm and soft.  It is so comfortable.  Both my husband and I have had amazing sleep since we got this.  I wouldn't call the mattress cooling but it certainly isn't overly hot to sleep in.  There is little to no motion transfer when getting in and out of bed or rolling over. I am so very happy I got this mattress.  Highly recommend!