I've posted this before, but I just don't see the fascination with carb tabs/drops. So many complaints about them.
Why not just batch prime with table sugar? If you're not looking for flavor additions (like, say, maple syrup), you can buy a five pound bag of table sugar for exponentially less than any other priming method. You measure up 1/2 - 2/3 of a cup for a 5 gallon batch (depending on exactly how much carb you want... check the link in my sig for a great priming sugar calculator), boil it all for a couple minutes in a cup or two of water, dump it in the bottling bucket, rack the beer on top.
It's that easy. It works 100% of the time. You can carb specifically to style if you want. You get zero residue or flavor contribution.