IMO, If you got a clean diet, (and eating a lots of protein in your meals) protein shakes are best used as snacks (with some carbs of some kind, e.g. fruit) in between meals so you dont go to many hours without.
And immediately after training, a gainer (both quick carbs and protein) is the most beneficient since you need to push up your glucus to be able to digest/absorb the protein. Eating protein with nothing else is not very efficient.
And proteinshake immideately before training is also good to have a full aminoacid-pool to minimize muscle breakdown from training.