In the March 2012 issue of CONSUMER REPORTS, the magazine takes on butter substitutes.
Typically these taste very unlike butter and it's a wonder anyone would buy them--other than the lower fat levels. But CR said LAND O LAKES SPREADABLE BUTTER WITH CANOLA OIL tasted best--but, it also has more calories and fat than most. Their tests indicate it closest to whipped butter with a slightly sweet dairy flavor. It has 11 grams of fat in a serving.
If you're concerned about that, they say try I CAN'T BELIEVE IT'S NOT BUTTER - LIGHT SPREAD (5 grams of fat) or BRUMMEL & BROWN 35% VEGETABLE OIL SPREAD (5 grams of fat). Both have a hint of sour cream/yogurt flavor. People who don't get enough nutrients through their regular diets might consider one of the products that include plant stanols or omega-3's (such as Benecol which is more expensive and has a slightly fatty feeling).
The ones receiving a "recommended" rating include:
Smart Balance Buttery Spread original
I Can't Believe It's Not Butter Light Spread
Brummel & Brown
I Can't Believe it's Not Butter Original Spread
Shedd's Spread Country Crock Original
Olivio Original Spread
Bear in mind: they tasted these products straight; even the lower-rated ones may taste better with food.