Let us speak here to the issue of complexity. Complexity in taste is where the entire mouth including all parts of the tongue are involved in the experience. It is the complex tastes that keep people coming back for more. When you think of products over time that have become huge successes and are not easily replaced by other products, they are generally quite complex. Take beer for example.
Beer is a beautiful blend of bitter, sweet, and salty.
To be complex, a product need not contain components for all 4 tastes. They must however, blend a number of the tastes and have several components within a taste category to intrigue the tongue. That is why a multiplicity of flavors in one product works better than one single, simple flavor. Another example is Coca-cola. Here is a beverage that is interesting because of its complexity.