The dark side of protein shakes is that many of them have soy. Soy is an estrogenic plant and should not be used by men or pre-menopausal women. Also the growing and processing techniques make soy toxic.

The other down-side to protein powder shake is the Sugar content. And sometimes hidden artificial sweetners.

I suggest going and purchasing pure whey protein and making your very own shakes with yoghurt or juice and a bananna or strawberries...you choose your fruit and blend well in a blender.

You should be able to buy bulk whey protein in a health food store.

Soy can make your hormones go crazy, male or female. Actually it has a lot of problems, should be okay if you're not having a lot, but if you are having a big serving everyday, then I'd research it first. But it doesn't mean whey is that much better.
Downside to large amounts of protein is damage to kidneys and liver. And heart/cardiovascular disease.

Whole Soy Story