Every day I try to eat a variety of protein sources. Protein powders are easy to absorb, and absorption is an important part of the mass-building process. However, whole-food animal sources of protein, such as eggs, dairy, fowl, red meat and fish, have complete, though somewhat different, amino-acid profiles. Some are higher in certain amino acids than others.
For optimal quality mass gains, I don't succumb to living mainly on powders. I Choose a wide variety of foods and include powders before and after workouts, and at times when convenience is essential. The variable amino-acid concentrations among different foods may exert unique effects on the body that result in better growth, as opposed to sticking with one or two protein foods or a couple of foods and a protein powder.