There are a few different types of Diamond mattresses, so it really depends on which one you're talking about. However, in general, Diamond mattresses are considered to be good quality. They use high-quality materials and construction, and they offer a variety of features that can appeal to different sleepers. For example, some Diamond mattresses have cooling technology built into them, which can be great for hot sleepers. Others have special layers designed to provide extra support for people with back pain. Overall, Diamond mattresses tend to be comfortable and durable, making them a good option for many people.