why does any sane person without specific digestive issues eat margarine these days?
every margarine trumpets itself as being "buttery tasting" and they all fall over themselves trying to be more like butter than butter.
so unless you can't digest dairy or you're a vegan, why on earth wouldn't you just eat butter? and if you're a vegan, i'd hope that you are more advanced than margarine: giant wad of transfat, artificial flavorings and dyes.
ew. if you can't have real butter, try another natural fat, like olive oil.
the only possible exception to this is if you are baking, because if you're squeamish about lard (and you SHOULD be squeamish about commercially available lard), it is superior for baking cookies, if you need flaky.
i STILL use butter for baking.