I tried this mattress a couple of times in the shop, and found it to be comfortable, with a supportive base but soft pillow top that you sunk into, giving a balanced feel. However, when it arrived, it felt considerably firmer than the one that I tried in store, with the pillow top not feeling as thick, and lacking the feeling that you could sink into it. I have had the mattress for 2 months, and in that time it has not felt like it was getting any softer, but I was very disappointed to find that the mattress is developing a not-insignificant sag in the middle (it was being used by a single person), to the point where if you try to sleep at the side, you can sense the slope towards the middle. After just 2 months this is incredibly disappointing, and does not bode well for the long term.
In addition, the cooling technology works very well when you are lying directly on the mattress as you do in the shop, but by the time you have added a mattress protector (also by Therapur) and fitted sheet, you can't really notice the cooling benefits any more.
Perhaps 1 star is a little unfair, someone who prefers a firmer mattress and is happy for it to be firmer than expected would not be as disappointed, but for me the noticeable dip towards the middle of the mattress is an issue that I could not overlook.
I have submitted an exchange under the Comfort Guarantee scheme for a medium-firm Silent Night mattress, as I didn't want to risk the same sagging issues by swapping to a medium firmness mattress from Therapur.