Very comfortable. Firm, but with a pillow top which means that there's a bit of cushioning as well as good support. It is of very good quality for the price too. I chose it because this sort of pillow top sprung mattress is supposed to be ideal for people who sleep on their sides, as hips and shoulders can sink into it a bit and so it doesn't make them ache as much. This seems indeed to be the case. My husband sleeps on his back as well, and finds the mattress good for that too.