We have always bought 'firm' rated mattresses, but over the last year or so my wife has been experiencing discomfort in her joints during the night. We noticed during recent holidays that with a softer mattress, she was much more comfortable, so we decided to consider replacing our three year old 'firm' mattress with a 'medium' rated one. After trying out several options in the Dreams showroom we chose the Therapur. I was concerned that it might not provide sufficient support for my back (being very tall) so, ideally, we would have chosen a mattress with different ratings on each side, but this option isn't available for 4'6" wide mattresses. However, having used the new mattress for around three weeks, it's proved to be definitely better for my wife and I can't say that I've noticed any negative consequences. I think the ActiGel top layer is what provides sufficient support for me whilst being soft enough for my wife. Only time will tell whether the ActiGel remains able to accommodate our individual requirements for the supposed 8 year life of the mattress, but we are certainly pleased so far.