Damn, I'm gone for the day and come back to a great debate. Ok, ain't got too much time to go into detail now, but short answers for now.
Post workout Wes is correct. Solid food IMO is best 99% of time.
I personally have always wondered if there was any advantage to taking slin only after workouts. Is there any real solid proof that these nutrients are getting used any better just because you happened to train a certain bodypart? Milos does at times advocate using it prework also so it is not written in stone for just post workout.
I am also not (totally) convinced that the growth that people get is due to a standard anabolic effect in the same manner that steroids work. I did once read about a guy who did not use carbs while taking slin and gained about 10 solid pounds and no fat gain. He used protein and fat as far as food goes. I do not remember at all about how he did this so don't ask. I wish I could remember, but even if I did I do not think that there is any advantage to it anyway.