It's all about the speed of results and the quality of the results. Protein can help you put on more lean muscle then bulk. There are different types of protein powders.

See my thread here for more details and stuff:
http://forum.logicalgamers.com/healt...ggestions.html

It most likely will answer what you want to know. If you already know all of that stuff, it comes down to your personal preference related to results.