I always use table sugar. I did use carbonation drops once, but didn't notice any difference and they cost more. I use half a teaspoon per 500ml bottle. I did use a small teaspoon in some of my early brews, but they came out too frothy.
I did have a hand grenade brew many many years ago in Australia when the weather turned hot. I think I bottled that one too early rather than over sugaring the bottles. That's rare, but I do keep my bottles in waterproof plastic containers just in case, as it was a messy experience.