I always look for something that blends easily with water, has no lactose, possibly a mixture of different proteins, a good array of vitamins/minerals and enough BCAA's to surpass what a pill would give.
I will mix a scoop in with a variety of drinks, depending on how I'm feeling.
I have pure egg whites ~ they mix well in almost anything, I have Lactaid, Soy milk and all the greeny drinks that have spinach, brocolli, wheat grass, etc.
If the protein doesn't mix or blend well, I'm not drinking it. You can assume the same thing will happen in your stomach.