Umm so vegetable glycerin has a caloric density similar to regular sugar but due to it's lower GI it's accepted as a sweetener that works with low carb diets - it has the same potency of regular sugar but doesn't raise blood sugar levels. From what I understand it has about 27 calories per teaspoon and is 60% as sweet as sucrose. Not sure what you want to use it for.. but when I need a sweetener, to make ice cream only, I've turned to coconut nectar and coconut crystals. Just my preference :) good luck!
Not sure on "vegetable glycerine", but glycerine was used to sweeten protein bars prior to the feds requiring more strict labeling. i.e. It was a cheap sweetener that the manufacturers could stick in without actually labeling as carbs. When the feds changed that, manufacturers had to label it as a carb (sometimes hidden in "Sugar Alcohols").
Does that mean it's bad? Not necessarily, but be aware it's similar in calories to carbs. No fructose though.