I know I've read before in the past that it was also compare to other PW drinks. I don't have the time right now to google it (that's why I posted in my original post to google it), but I remember reading that chocolate milk has the right ratio of fat, carbs and protein for a post workout drink.
FWIW I make a Whey Protein Isolate & cottage cheese PW shake with fat free milk, and eat a banana. This way I get a fast & slow digesting protein and a fast carb, I get my fat from almonds. But I think that chocolate milk may be a good alternative.