Mattresses come in different options ranging from firm to plush, pocket coil to interactive coils and memory foam. Firmer doesn't necessarily mean better in terms of a good mattress. In the end it comes down to what feels good to you.
When shopping for a new mattress, test different ones out and find the one that suits you best. We suggest that you wear comfortable clothing, and devote enough time to find the right choice. Regardless of the bed you pick, twin to king, finding the right mattress is the most important part of the decision.