I've never even bothered with taking one particular AA at a time, like Arginine. I've done Glutamine, but always used that with meals- or did that really matter for your question? I can't say I really noticed too much with Glutamine, though some swear by it.
I saw one time that Mike Matarazzo loved his BCAA's and so I tried Optimum Nutrition's BCAA powder, and that was good. I could noticeably feel the effect it had on me recovery wise. Again I did take this with a meal though, and each meal had something like tuna, steak or eggs to make a complete protein too.
I do the Milos style shakes, and I love the way I'm able to train with those.