Margarine has had a very interesting and even controversial history throughout the years since it's invention, but there are many reasons why I believe that butter is a much healthier option.
Margarine - Wikipedia
Margarines: Historical approach, technological aspects
The History of Margarine (And Why Butter Is Better) - Our Heritage
Can I use margarine instead of butter in steaks? - Quora
The Margarine Wars
Is Country Crock butter or margarine? How is it made? - Quora
Can heart patients consume butter? Is margarine a better option
Is it better to make cakes with butter or margarine? - Quora
Margarine Was Created For An 1869 Competition
How to Make Homemade Butter - Roots and Refuge
The Facts About Butter And The Hard Truth About Margarine