We love out Serta iComfort 300 mattress. We had a s Serta foam topper on our old mattress so we were familiar with the foam concept, but this is much firmer than the toppers. The most important thing that we like is that we don't feel each other's movements like we did before. This is a great feature of the firm mattress. We don't disturb each other when coming to bed or getting up in the morning.