Pass the butter please. Margarine was originally manufactured by fatten turkeys. When it killed the turkeys, the people who had put all the money in to the research wanted a pay check so they put their heads together to figure out what to do with this product to get their money back.
It was a white substance to no food appeal, so they added the yellow coloring and sold it to the people to use in place of butter. How do you like it? They have come out with some clever new flavorings.
In reality Napoleon gave a prize to the first person to find a cheap butter substitute for his army, which is why margarine was invented by a French chemist. Modern margarines are much healthier than older ones, and some are said to have healthier fats (Omega-3, and so on) than butter.
Butter can hardly be said to be unprocessed, being a concentration of the fats in milk, with much of the goodness lost - Calcium, proteins, etc.
From what I've heard, tub margarine is better than butter, but butter is better than stick margarine (which has trans-fat). However, despite it's "bad rap," Lard actually has less saturated fat than butter.
None of it is "healthy," but if you eat them in moderation, you'll probably be fine.