I've tried 5 different toppers so far (discovering I'm allergic to memory foam in the process!) and this is my favourite cool weather topper.  It's like lying on a very thick duvet and needs to be shaken out to plump it up every few weeks.  It has made a noticeable difference to my hard mattress and I'm much comfier now.  It is quite hot to lie on, so I don't know what I'm going to do in the summer, but it's very cosy now.  There is a limit to how much difference a layer of polyester cam make, but for this price range,  it's the best I've found so far.