There are certainly a lot of misconceptions about Stevia.  I had never even heard of the herb until a few years ago.  Now that Stevia is becoming more mainstream, there are a lot of different varieties available.  Most have fillers in them to make it measure for measure like sugar.  The fact is, though, that Stevia is 250 to 300 times sweeter than sugar, so it only takes a small amount of pure Stevia to equal the sweetness of sugar.

My favorite brand of Stevia is SweetLeaf.  It is an all natural Stevia, with no fillers.  There is no bitter aftertaste.  You may need to modify your Stevia measurements if you are using another brand of Stevia.

Update 8/13/20:

Stevia was not allowed to be sold as a food additive by the FDA for a long time.  It is now.  What changed?  Scientists figured out how to extract the part of the plant that gives it the intense sweetness:  Rebaudioside A (reb A for short).  It can now be produced synthetically.  Which means people can make money from (and the reason the FDA now allows it’s addition to foods)! Now you see stevia in all of the big brand name items, like Pepsi, Russel Stover, Splenda, etc.

It is still best to look for the natural plant, not the adulterated version that chemists have messed with.

I now currently use the Kal brand of liquid stevia.  It is all natural, with no weird additives.  It also has no bitter taste.  The powdered form of Kal stevia does have a bit of a bitter taste, which is why I mainly stick to the liquid version.

Here is a great resource for any questions/concerns you may have about Stevia.

Updated 8/13/20.