Buying a new bed but confused with mattress choices, any advice?

[Linnet]

Dh and I have decided to buy a new bed, we're going to be boring and grown up and get a divan but we are confused by the choices of mattress, should we get a Cushion top mattress or a deep quilt?

thanks

Argos catalogue explains the differences nicely. I'd go to a bed shop and find out whats the most comfortable.