Butter is better! Cow->Cream Separator->Churn->Rinse
The butter from cows naturally has a little yellow tint to it, but butter made from sheep and goat milk is snow-white, because sheep and goats are extremely efficient at converting beta carotene to vitamin A and using it instead of leaching it out.
I remember when my mom told me about the gray margarine when I was quite young. I never liked the stuff anyway.