im on the side of a casein and whey mixture for a quick shot and sustained release of protein however it depends what type of training your doing because too much protein is a waste and counter productive in my experience protein is usually overdone in many cases and its important to have good carbs with the protein otherwise the protein wont go where you want it to go and your body will try and burn it for energy, but whey by itself is not the most complete of proteins of course if your mixing them with milk then the aminos from the milk will complete the protein anyway.