I use the NOW brand unflavoured, sweetener-free whey protein isolate. Never had problems with it (in case you will be using it because you are sensitive to all the crap and sweeteners they through into most protein powders these days), and the quality is as good as you'd expect from now. It smells and tastes like skimmed milk powder and mixes easily. I use it in blends too, for my portein smoothies. Its flavour is very neutral (doesn't dominate on the other flavours in the recipe) so yeah it's pretty good