Soy milk, (soy products in general) is highly processed as pointed out previously. Dairy isn't all that great for humans (although I do take half & half in my coffee).
A good alternative is almond milk which is sold in original, vanilla, and chocolate flavors. My daughter has asthma and in looking for alternatives to milk, I discovered almond milk. We are vegetarian, but most of the meat substitute products available are not really very healthy choices.
I don't know how great any of it is for the environment, I make choices based first on health concerns.