I'm gonna say the best protein I've taken is the CORE Protein Shake by MyntProducts.com
Little bit pricey, but high quality at $59 price for 25oz bag. Take 1-2 scoops serving with 8fl oz of water.
It's an all natural, soy free, gluten free protein powder. Uses what they call TruCelle which is a restructured micellar casein.
I got the vanilla and chocolate flavors. Taste was pretty good. Didn't gag on it.