Spock's Spacesuit For Sale.

Firstly, if a recipe calls for butter, use butter. Margarine is not a version of butter - it is as close to butter as astroturf is to fresh grass.
Secondly, the Science Dump article does not answer the question posed in the title of this article.
If you really want to know which is better for you, read this article and check the links contained in it. http://tinyurl.com/p2b6s3p
And, as the Guardian article concludes: "Don't hold your breath waiting for a climb-down on saturated fat. The healthy eating establishment will choke on its low-fat cornflakes before it coughs that up."