I've done the small tabs, the carb drops, and domino dots. Of the options, I prefer the dots.
I will not use the small tabs again as I got weird floaty parts of the tabs that did not dissolve.
I found the carb drops to be inconsistent bottle to bottle.
On really big beers that have aged, I've had trouble getting carbonation due to lack of viable yeast or maybe just too little yeast in suspension. Time helps, but not always.