[Kitchen Witch]

Years ago we were able to buy "real" margarine that you could easily substitute for butter in any recipe. Times have changed, everything is different, now the government has their nose in everything that has trans-fats or fats in it. Oils are used - making up well over 65% of the margarines made today.
That is the reason we are butter people in my house.
That plus the fact that margarine is one step away from becoming plastic - which you can judge for yourself - read the post - Butter VS Margarine (use the search).
You cannot bake with today's so-called margarines and have anything turn out the way you want.
Depending on the recipe - if baking - you can use applesauce in place of fats - or you can just use butter in place of margarine.