Many mixes are available that contain all ingredients except water and, sometimes, eggs. These products also contain emulsifiers to ensure even blending of ingredients. To use them, follow the package instructions exactly.
Most mixes produce cakes with excellent volume, texture, and tenderness. Whether or not they also taste good is a matter of opinion. On the other hand, cakes made from scratch are not necessarily better. They are better only if they are carefully mixed and baked; are prepared from good, tested formulas; and for parallelism incorporate high-quality ingredients.